屋面卷材防水施工,在天沟、檐沟纵向找坡不应小于()。 A. 0.3% B. 1% C. 0.5% D. 2% 参考答案:B
第19题: [单项选择]So far there is no proof ______ spaceships from other planets do exist. A. which B. that C. how D. what 参考答案:B 答案解析:[解题指导] 此题考查句法、代词。依据句意,填充处缺少一个关系代词引导句子spaceships from other planets do exist作名词性定语从句修饰proof。辨明选项的各自含义