There are five pairs but I’m at a loss which to choose.A. to be chosenB. to choose from

问题补充：

There are five pairs , but I’m at a loss which to choose.

A. to be chosen

B. to choose from

C. to choose

D. for choosing

答案：

A. to be chosen

(答案→)B. to choose from

C. to choose

D. for choosing

解析：句意是“有五双可供选择，我拿不定主意从中选择哪一双”，而不是选择五双。