单选题 No sooner ______ they started to work.
A. had they got to the plant then B. had they got to the plant than
C. had they got to the plant when D. they had got to the plant than

【正确答案】 B
【答案解析】[解析] 语法结构题。No sooner...than“一……就”为一固定句型，故排除A、C，no sooner位于句首通常要用过去完成时态的倒装，故排除D。则B为正确答案。句意：计划一制定，他们就着手实施。