问题
多项选择题
港口与航道工程配制混凝土的基本要求有()。
A.强度要符合设计要求
B.耐久性要符合设计要求
C.应满足设计构件的抗裂和限制裂缝宽度的要求
D.应满足施工中对于坍落度损失的要求
E.应经济合理
答案
参考答案：A, B, D, E
搜题请搜索小程序“爱下问搜题”
港口与航道工程配制混凝土的基本要求有()。
A.强度要符合设计要求
B.耐久性要符合设计要求
C.应满足设计构件的抗裂和限制裂缝宽度的要求
D.应满足施工中对于坍落度损失的要求
E.应经济合理
参考答案：A, B, D, E
It says that bats (蝙蝠) are almost blind (瞎的). Do you know _______ the bat finds the way? In fact (事实上), bats find their ways ______ the help of their ears. Bats make a ______ that we can’t hear at all. They cry when they fly and the echoes (回声) of these cries come back to their ______. In this way they can know where they should go. Bats fly out in the _______. In the daytime, they just stay together in their homes. When the evening comes, they begin to _______ and look for _______. The next morning, they come back from work to sleep _______ the evening. Some people _______ that bats are bad animals. In fact, they are very ______. They catch and eat pests (害虫). This is very good for people.
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