基本语法。

1. We must protect the water here from____    (pollute).

2. The outside of the earth       (make) up of many  different plates.

3. Two         (three) of the students are girls in our class.

4. People standing on the top of the high mountain breathe much        (hard) than the people at the foot  of 

    the mountain.

5. These unwanted things should         (take) away at once.

「一昨日」的正确读音是（）。

A、いとひ

B、いちさひ

C、おととい

D、おとい