materials should be prepared
需要准备的资料
what kind of materials should be prepared
需要准备什么资料
建议在句末加in advance,强调是事前准备
What kind of materials should be (可以加上主语亦可不加)prepared ?
What kind of material should be prepared?
关于你要求提供的测试报告,不知道工厂为什么没有回答?
What information shuld be prepared?