Previewing is a technique of allowing your eyes to travel rapidly ______ a page,stopping here and there to register the main idea.

Oneofthemainreasonsisthatmakingfurniture______vastquantitiesoftrees.

学生常通过调查、采访、研究等 ______活动获取信息。

我们平常说的英语“双基”教学是指_____和____。

备课就是写教案。