We had just covered half the journey________the engine failed and we could do nothing but wait for help.
A．before B．since
C．when D．until
We had just covered half the journey________the engine failed and we could do nothing but wait for help.
A．before B．since
C．when D．until
C 解析： 句意为：我们刚走了一半这时发动机就出故障了，我们别无选择只能等着救援到来。when就在这时；突然……。before在……之前；since自从；既然；until直到。