听力原文：M: Welcome! What can I do for you？
W: I'd like a bottle of Coca Cola and some cakes.
M: OK. Here you are.
Q: Where are they？
（19)
A．In a food store.
B．In the post office.
C．In the police office.

According to the conversation, what factors influence the color of water？ Click on two answers.
A．Waves on the surface
B．The depth of the water
C．Sediments in the water
D．The water temperature

What can be inferred about a lake with brown water？
A．The lake is not safe for swimming.
B．The lake has a sandy bottom.
C．The water contains suspended particles.
D．The water is very deep in the center of the lake.

听力原文：What's your favourite sport？
（13)
A．Eggs.
B．Swimming.
C．Reading.

Listen again to part of the lecture. Then answer the question. Why does the professor say this:
A．To stress the mysterious nature of severe immune responses
B．To argue that anaphylaxis is mainly the result of bad luck
C．To point out that scientists disagree over what causes allergies
D．To suggest that people are crazy to eat offending substances

听力原文：Can the boy swim？
（14)
A．No, he can't.
B．Yes, he can't.
C．No, he can.