If it ________ for the heavy rain then, we would have arrived here ahead of time.

求不等式组$\left\{\begin{array}{c}2\left(x-2\right)\le 4x-3\\ 2x-5<1-x\end{array}\right.$的整数解．

下面是一份关于中国占代江南地以人口数量的统计表。该表反映了（  ）

根据短文内容，选择正确答案。
D
    The students are having their chemistry (化学) class. Miss Liu is telling the children what water is like. After that, she asks her students, “What's water?”No one speaks for a few minutes. Miss Liu asks again, “Why don't you answer my question? Don't I tell you what water is like?”
    Then a boy puts up his hand and says, “Miss Liu, you tell us that water has no color and no smell. But where can we find such kind of water? The water in the river behind my house is always black and it has bad smell. "Most of the children agree with (同意) him.
    “I'm sorry, children.” says Miss Liu. “Our water is getting dirtier and dirtier. That's a problem.

对温室大棚里的农作物，采取适当措施能提高光合作用效率，增加产量，以下措施不能起到这种作用的是