(·凉山一模)Life is like riding a bicycleyour balance you must keep moving.A. KeepingB.

问题补充：

(·凉山一模)Life is like riding a bicycle. your balance, you must keep moving.

A. Keeping

B. To keep

C. Keep

D. Being kept

答案：

A. Keeping

(答案→)B. To keep

C. Keep

D. Being kept

解析：B句意：生活就像在骑自行车。为了保持平衡，你必须不断前进。根据句意可知此处需用不定式作目的状语，故选B项。