Past simple or present perfect simple or continuous?

Put the verbs into the correct tense (simple past or present perfect simple).

1.   A: (you / taste / ever) ____________sushi?
2.  B: Yes, I (eat) ________ sushi at least five times so far.
3.  A: When (you / eat)  _________ sushi for the first time?
4.  B: I (eat) _________ sushi for the first time on my dad’s 50th birthday. He (invite) _______ the whole family to a Japanese restaurant.
5.  A: (you / like) ________ it?
6.  B: Absolutely. In fact, it (be) _______ so good that we (be) ________ to that restaurant three times yet. And on my mum’s birthday, we (order) _______ some sushi and (have) _______ it at home.

Fill in the correct form (Present Perfect Simple or Present Perfect Continuous).

1.  You (eat / not) ______ up yet.
2.  He (speak / not) _______ on the phone for half an hour, just a couple of minutes.
3.  They (work / not) _______ since 5 o’clock. They just started an hour ago.
4.  We (know / not) _______ them for a long time.
5.  She (hang / not) _______ up all the pictures yet.

How do dogs “see” with their noses?

You may have heard the expression that dogs ‘see with their noses.’ But these creature’s amazing nasal architecture actually reveals a whole world beyond what we can see.

Watch a video about how dogs smell and choose the best answer for each question.

1. What does a vomeronasal organ do for dogs? Choose the answer(s) from the following list:

A. Allows them to detect direction of smell
B. Alerts them to various emotional states
C. Lets them identify potential mates
D. Detects hormones of other organisms

a) A only

b) D only

c) A, B, and C

d) B, C, and D

2. Dogs have how many specialized olfactory receptor cells?

a) 5 million

b) 300 million

c) 7 million

d) less than 100

3. Dogs can smell separately with each nostril. This is an advantage. Why? Choose the answers from the following list:

A. They can exhale out one nostril and inhale in the other
B. They can determine what is out there
C. It allows them to keep their nose moist and spongy
D. They can determine the location of the smell

a) All of the above

b) B only

c) A and C

d) B and D

4. Olfaction bypasses the thalamus and goes directly to the brain, making the dog’s senses _____

a) Visceral and more immediate

b) Slower and more time consuming

c) Unable to detect certain odors

d) Only able to detect food sources

5. The slits in the side of the dog’s nose are essential because _____.

a) They keep the nose moist

b) They inhale through them

c) They are directly connected to the vomeronasal organ

d) They help create swirls of air that draw in more odor molecules

6. Dogs are said to be a man’s (or woman’s) best friend. Give four examples of how dogs assist humans. Based on what you learned about canine olfactory senses, predict how dogs may continue to aid humans in the future. How do you feel about using dogs in service to humans?





Lesson by Alexandra Horowitz, Guilherme Araujo, Iuri Araújo, and Alex Gendler

How we conquered the deadly smallpox virus

For 10,000 years, humanity suffered from the scourge of smallpox. The virus killed almost a third of its victims within two weeks and left survivors horribly scarred. Thanks to a Buddhist nun, a boy, a cow, a dairymaid and physician Edward Jenner — who first stopped the spread of this disastrous disease, to make us smallpox-free today.

Watch a video about the deadly smallpox virus and choose the best answer for each question.

1. How did the smallpox virus infection spread most frequently?

a. Through the air

b. Through the soil

c. Through blood

d. Through feces

2. What percentage of infected people would die after smallpox virus infection?

a. 13%

b. 30%

c. 33%

d. 3%

3. What percentage of people would die after variolation?

a. 13%

b. 30%

c. 33%

d. 3%

4. What did they use in the 1700s to inoculate healthy people for variolation?

a. Pus from the utters of a cow

b. Pus from a lymphnode of an infected patient

c. Pus from scabs of an infected patient

d. Pus from the fresh sores of an infected patient

5. How intense were the clinical symptoms of cowpox as compared to smallpox in humans?

a. More intense

b. Less intense

c. Same intensity

d. We cannot compare them as they are caused by two different viruses


Lesson by Simona Zompi, animation by Augenblick Studios.

How do vaccines work?

Watch a video about a vaccine and choose the best answer for each question.

1. Edward Jenner succeeded in creating a vaccine against smallpox by injecting patients with material of which disease?

a) Smallpox

b) Cowpox

c) Cattle virus

d) Measles virus

2. What is the function of innate immune response?

a) Act very rapid as a first line of defense to eliminate the infection

b) Trap microbes so they cannot spread in our body freely

c) Coordinate and support adaptive immunity

d) All of the above

3. What is the main advantage of live attenuated vaccine?

a) It provides more durable immunity; boosters may be required, though less frequently than would otherwise be necessary

b) It is safer than other kinds of vaccines

c) It does not cause any severe side effects or complications

d) It is suitable for people with any type of health

4. Which is not true about subunit vaccines?

a) They can be designed using molecular biology technique

b) They are less harmful than live attenuated vaccine

c) They generally are made of polypeptide or oligopeptide

d) They provide lifetime protection

5. Since we have our immune system to protect us from disease, why do we still need a vaccine?

a) Because some diseases are too severe for our immune system

b) Because adaptive immunity takes days to weeks to initiate a response and sometimes it is too late

c) Because some people are immune deficient or have weak immune systems

d) All of the above


The chemistry of cars

There are over one billion cars in the world right now, getting people from point A to point B. But cars aren’t just a mode of transportation; they also teach an excellent lesson in chemistry. Cynthia Chubbuck navigates the intricate chemistry performed in our car engines that keep them from getting too hot or too cold.

Watch a video about the antifreeze and coolant and answer the questions.

1. What kind of liquid can absorb the heat from an internal combustion engine?




2. Why do we need the cooling system?




3. What will happen if our car has water in the radiator and gets cold enough to freeze?




4. What is the highest recommended mixture of water and ethylene glycol?




5. What is the new freezing point and boiling point after using antifreeze and coolant?


The Hippo That Lives In A House

Listening Quiz

Choose the best answer for each question.

1. Who does Jessica have her afternoon snack with?

a) Tony

b) the dogs

c) the crocodiles

2. Which room is Jessica’s favorite?

a) the bedroom

b) the kitchen

c) the bedroom

3. What does Jessica enjoy before go to bed?

a) a nice cup of tea

b) a massage

c) The video doesn’t say

4. What is Tony Joubert’s job?

a) He is a wildlife photographer.

b) He is a game warden.

c) He is a hunter.

5. What has Jessica broke in the house?

a) a sofa and a bed

b) lots of vases

c) a chair and a table

6. What other types of animal has Tony raised?

a) giraffes, tigers and bears

b) The video doesn’t say

c) elephants, buffaloes and lions

7. What does Jessica drink twice a day?

a) weak hot tea

b) weak sweet coffee

c) strong black coffee

8. How long do hippos usually live?

a) The video doesn’t say

b) into their forties

c) into their fifties


Remembering Nelson Mandela

Nelson Mandela Listening Quiz

Choose the best answer for each question.

1. When was  Nelson Mandela born?

a) July 18, 1919

b) July 18, 1918

c) July 19, 1919

2. ANC is short for…

a) The African Nation Congress

b) The African Nation Convention

c) The African Nationalist Congress

3. When did  Nelson Mandela become head of the ANC’s Youth Wing?

a) in the 1960’s

b) in the 1950’s

c) in the 1940’s

4. When did South African government ban the African Nation Congress ?

a) in 1960

b) in 1963

c) in 1968

5. How much time did Nelson Mandela spent in the notorious Robben Island prison?

a) 15 years

b) 18 years

c) 21 years

6. When was Nelson Mandela finally released from the prison?

a) in 1987

b) in 1990

c) in 1994

7. How long did Nelson Mandela serve as President of South Africa?

a) 5 years

b) 10 years

c) 15 years

8. What did Nelson Mandela do on his 80th birthday?

a) the video doesn’t say

b) he celebrated his released from prison

c) he got married