hands and knees Helen Thayer got the tent up.A. InB. AtC. WithD. On

问题补充：

hands and knees Helen Thayer got the tent up.

A. In

B. At

C. With

D. On

答案：

A. In

B. At

C. With

(答案→)D. On

解析：介词词义辨析题。 A. In 在里面 B. At在C. With用D. On 依靠句意：依靠手和膝盖海伦支起了帐篷。根据语境选D