Question

We want to know       he will come back, as we are worried about his safety.

A．how often

B．how soon

C．how much

D．how long

Answer 1

B

试题分析：how often多久一次；how soon多久；how much多少钱；how long多长。句意：我们想知道他还有多久回来，我们很担心他的安全。结合语境可知选B。