[单项选择]All mammals have hair, but not always evident.（）
A. but it is not
B. but it is
C. but they are not
D. but they are

[单项选择]All mammals have hair, but not always evident.（　）
A. but it is not
B. but it is
C. but they are not
D. but they are

[单项选择]根据下面短文回答下列问题。
All of us have hair on our heads. There’s some hair over our eyes and in our noses.
The hair on our heads can help us in cold days. It can help keep the cold off. It’s like a cap to keep the heat in. In hot days it keeps the heat off like a cap, too.
The hair over our eyes can keep the rain and the dirt out of our eyes in windy and rainy days. We call them eyelashes.
When we breathe, the hair in our noses can clean the air and keep the dirt out before it goes into our bodies.
The hair on our heads are useful ______.
A. in winter
B. in summer
C. all the time

[单项选择]The class of mammals embraces nearly all warm-blooded animals except the birds.
A. takes on
B. takes over
C. takes in
D. takes up

[单项选择]

I always have a difficult time choosing original birthday presents. My imagination never seems to get beyond ties, handkerchiefs, or pairs of socks. But, strangely enough, it did not take me long to decide on Tom’s birthday present. For the first time in my life I had a good idea--I would buy him a bottle of champagne. Before the party began, Tom suggested that I should open the bottle. I put it between my knees and began to pull, but it remained firmly corked. Soon a crowd gathered round to watch the fight between me and the bottle. I could hear all sorts of" helpful" suggestions from the guests like "Break the top off", "Use your teeth!" etc. But I was losing the bottle. We were struggling on the floor together, when all of a sudden there was a loud "pop!" and the cork shot up into the air, while the angry bottle showered everybody with champagne!

What suggestion of the guests is tree（）
A. Break the top off.
B. Use the mouth.
C. Step by step.
D. Put it on the floor.