Question

He doesn’t have the habit of planning his travel expense, so he won’t know what to do _______ the money runs out.

A．once

B．before

C．unless

D．though

Answer 1

A

连词辨析。A.一旦     B.在……之前 C. 除非 D. 尽管。句意：他没有计算旅行费用的习惯，因此他不知道一旦钱用完了该怎么办。故选A。