日本免费精品视频,男人的天堂在线免费视频,成人久久久精品乱码一区二区三区,高清成人爽a毛片免费网站

Practice

Warm Up

First, circle one of the words inside the bracket to complete each sentence with your own choice. Then listen to the recording to check the correct answer.

1. Flowers completed most of their evolutionary process in (30 / 13)million years.

2. Cats can see the world only in shades of (blue and yellow / black and white).

3. When we are hungry, thinking about food sends signals to our (brain /digestive organs).

4. Corn plants in the field often get invaded by (caterpillars / wasps).

Part I

Practice 1

Listen to part of a talk given in a biology class. Pay attention to the main topic or idea and answer the question.

Q. What is the main idea of the lecture?

A The evolution of flowers is completely unknown.

B Flowers evolved in quite a short period of time.

C Among scientists, biologists work the fastest.

D Flowering plants actually appeared 30 million years ago.

Listen again and fill in the blanks.

Prof(W): Scientists say flowers first on Earth about 140 million years ago. Then, by about 30 million years later, flowers completed their evolutionary processes. Well, the interesting thing is that to a biologist, 30 million years of time is, so the evolutionary process of flowers is to be very fast. That's why a group of scientists are now trying to solve the mystery flowers' fast evolution. to solve this mystery is to make a full of a plant called "Amborella". The Amborella is a very important plant for the scientists because it is the flowering plant. And now, many scientists hope that it can provide clues about flowers' and evolution.

●evolutionary adj. of the history of the development of a biological group

●genetic map a graphic representation of the structure of a single gene

●flowering plant a plant that produces flowers and fruit

Practice 2

A Listen to part of a lecture in a science class. Pay attention to the main topic or idea and answer the question.

Q. What is the main topic of the lecture?

A Ambushing predators

B Detecting a cat's movement

C Colorblind animals

D Cats' vision

B Listen again and fill in the blanks.

Prof(M): Now, let's turn our attention to how cats . Some people consider cats to be . It is because cats see the world in of blue and yellow, much people who are red-green colorblind, so maybe cats' color vision isn't as humans. However, cats' vision has to detect movement. Have you seen a cat pounce when moves? Then you've probably also that it doesn't move when the toy still. That's because cats are ambush predators. This

means that cats still and moving prey. That's how ambush predators their prey. Also, the position of the cat's eyes, on the front of the head, makes the cat judging distance.

●colorblind adj. being partly or totally unable to recognize one or more colors

●shade n.the gradation of darkness

●evolve v. to develop or achieve gradually

●detect v. to discover the existence or presence of a thing

●pounce v. to make a sudden approach

●stil adj.not moving

●ambush n. hiding in order to attack by surprise

●predator n. an animal that lives by killing and eating other animals

●prey n. animals hunted or killed by another animal for food

Practice 3

AListen to part of a conversation in a school office. Pay attention to the main

situation and answer the question.

Q. What is the conversation mainly about?

A The difficulty of being a first year student

B The problems with studying for a course

C How to make course selections

D Looking for places on campus

B. Listen again and fill in the blanks.

M: Hi, there.

W: Oh, hi. I am having some with my course . Can you help me?

M: Sure. What seems to be the problem?

W: Um ... everything, actually. You see, I'm a first year student and I understand the course names. I mean, the codes and numbers...

M: Well, I understand. Many first year students have with it.

W: I'm glad to hear that. I know I'm not the only one.

M: So tell me what courses you want to take. Then I'll help you find them in the course .

W: Thanks.

●selection n. the act of making choices; a carefully chosen collection of things

……