题目内容：

完成句子 (共5小题；每小题2分，满分10分)

1.Walking does need a bit of practice ________ ________ ________ _________ _________(既然重力改变了).　

2.He did not look forward to __________ _________ _________(欠债) because his restaurant was no longer popular.

3. At that time people would starve if food _________ __________ __________ __________(难以找到), especially during the cold winter months.

4.So ________ ________ _______ _______(是否生命能继续延续) on the earth for millions of years to come will depend on whether this problem can be solved.

5.You must come ________ _______ ______ (任何时候你想来) and have ________ _______ ________ (任何你喜欢吃的东西).