单选题The chairman requested th

问题补充：

单选题Thechairmanrequestedthat＿＿＿＿＿＿＿＿＿＿＿.A.the members studied the problem more carefullyB.the problems were more carefully studiedC.the problems could be studied with more careD.the members study the problem more carefully

答案：

D解析在suggest, demand, request，require(要求)，order(命令),insist（坚持），advise（劝告）等动词之后的宾语从句中，谓语动词要用(should) do，同时还应注意语态。