Question

【题目】It won’t be long ______ self-driving cars appear on the market.

A. until B. after

C. when D. before

Answer 1

【答案】D

【解析】

考查连词。句意：不久后无人驾驶汽车就会出现在市场上。本句为句型it is not long before不久后，故选D。