根据中文提示，用词组的适当形式填空，每空一词。

1. Forests can __________ the water __________ (防止) washing the earth away.

2. I hope you can __________ me __________ (提供) some information about Fujian.

3. Don't forget to __________ __________ (关掉) lights before you leave the room.

4. We __________ __________ (应该) to plant some trees in our new school evey year.

5. __________ __________ (到目前为止), our government has taken many measures to control the

    population.

参照美国阅读学家GR施道弗博士的理论，可以得出一个检查阅读效率的公式：X=S※L。该公式解释为：阅读效率取决于下列两项指标（）。

A.阅读速度和理解率

B.阅读速度和准确率

C.阅读准确率和理解率

D.阅读速度和误差率