保温屋顶为了防止保温材料受潮，应采取（）措施。
A、加大屋面斜度
B、用钢筋混凝土基层
C、加做水泥砂浆粉刷层
D、设隔蒸气层
参考答案：D
— Guess what! I have got A for my term paper.
— Great! You _____ read widely and put a lot of work into it. [ ]
A. must
B. should
C. must have
D. should have
犁侧板在工作时紧靠沟墙，用来平衡犁在翻土时产生的侧向力。（）
