写单词。

1. Can you name the four great ___________(发明) of China?

2. About ten ___________(百分之) packaging is plastic.

3. The Rocky ___________(山脉；山峰) are the biggest ones in North America.

4. ___________(地理) is the study of the world's places.

5. We ___________(成功) to have the broken bike repaired well. We are very happy.

6. Maybe in the future all the cars, buses will be ___________(电的)

7. We use wood from trees to build houses and ___________(家具)

8. The rose is one of the ___________(漂亮) plants in the world.

9. Let's do the ___________(试验) and see what happens.

10. ___________(保护) the environment is everyone's duty.

混凝土使用的拌制水的pH(酸碱度)应不小于( )。

A．7
B．5
C．4 D．6