(A) What we know about certain diseases (B) are still not sufficient to prevent them (C) from spreading easily (D) among the population.

A. I can’t carry out my mountain climbing because there are many cats and dogs falling out the sky.

B. It is the heavy rain that prevents me from climbing the mountain today.

C. I find it rather hard to climb the mountain despite a heavy downpour outside.

D. The heavy rain makes it possible for me to continue going climbing today.

A. to prove that they have got more tourism than they handle.

B. to tell us how wealthy their people are.

C. to suggest that these cities lack places of historic interest and scenic beauty.

D. to show that they are not good cities in terms of geography and climate.

A. He was obliged to study for the exam by his parents.

B. He was made to study for the exam by his parents.

C. He is made to study for the exam by his parents.

D. He was made study for the exam by his parents.

A. essential

B. needed

C. helpful

D. successful

A. dictation

B communicate

C. occasion

D. reservation

A. lonely

B. single

C. unique

D. once

A. theme

B. ethnic

C. thunder

D. honey-mouthed