单项选择题

The main function of the shell is ______.

A．to strengthen the pilings of the house
B．to give the house a better appearance
C．to protect the wooden frame of the house
D．to slow down the speed of the swelling water

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热门试题

单项选择题

The huge increase in world production and population ______.

A．has made the world a worse place to live in
B．has had a positive influence on the environment
C．has not significantly affected the environment
D．has made the world a dangerous place to live in

单项选择题

According to the author, most students ______.

A．believe the world's environment is in an undesirable condition
B．agree that the environment of the world is not as bad ms it is thought to be
C．get high marks for their good knowledge of the world's environment
D．appear somewhat unconcerned about the state of the world's environment