【推荐1】I don’t know the reason___________ he didn’t come to the meeting yesterday morning. (用适当的词填空)

【推荐2】The reason ________ he was late for school was that he was knocked down by a bike. (用适当的词填空)

【推荐3】单句语法填空
1. Many animals move from one place to another __________ certain times of the year；this __________（move）is called migration．
2. A team of scientists __________（lead）by professor Eli Schlizerman at the University of Washington has now found the answer．
3. The solution __________ the mystery of the monarch’s __________（amaze）ability comes at a time __________ it is in serious trouble．
4. Its population _________（crash）by as much as ninety percent in the last few years；_________（unfortunate），human activity is the main reason __________ the monarch numbers are falling．
5. A better understanding of the monarch’s behaviour has however led to a greater __________（aware）and __________（appreciate）of this creature．
6. The __________（much）we know about these delicate creatures，__________（great）the chance they __________（survive）．
7. We are in a position __________ we may lose a great deal of money．
8. It is so wet there that the trees are extremely tall，some __________（measure）over 90 metres．
9. Now we have to raise the public __________ of environmental protection because many people in our country are not __________ of the environment we live in is becoming worse and worse．（aware）
10. The more we get together，the __________（happy）we will be．
11. Plants and animals， including humans，need food and water __________（survive）．