问题补充：
After climbing the hills in the natural park for hours, my legs _under me and I failed to keep pace with others．
A. gave out
B. gave up
C. gave in
D. gave away
答案：
(答案→)A. gave out
B. gave up
C. gave in
D. gave away
解析：A．gave out 分发，精疲力竭，用完，B． gave up放弃，C． gave in屈服，D． gave away泄露，赠送，句意：在自然公园爬山几小时后，我的腿精疲力竭，我赶不上其他人了。根据句意选A。
