Cycling is a good way of exercise and is quite easy . A. to do B. to be doneC. doingD. bei

问题补充：

Cycling is a good way of exercise and is quite easy .

A. to do

B. to be done

C. doing

D. being done

答案：

(答案→)A. to do

B. to be done

C. doing

D. being done

解析：原句意思是，骑自行车兜风是一种很好的运动，并且很容易做。分析句子结构，形容词后的不定式是主语补语，答案为A。