1. Historians have long been puzzled by dots, lines and symbols which have been engraved on walls, bones, and the ivory tusks of mammoths.
    长期以来，历史学家一直对雕刻在墙壁上、骨头上、古代长毛象的象牙上的点、线和形形色色的符号感到困惑不解。

2. He had had a long and uncomfortable trip, for he had been confined to the wooden box for over eighteen hours.
    他经历了一次漫长而又难受的旅程，因为他在那木箱里闷了18个多小时。

3. How long have you lived here?
    您在这里住了多长时间？

4. How long can I hold my breath?
    我能屏息多长时间？

5. However, this is just a beginning, and there is still a long, long way to go.
    然而，这仅仅是开始，前面的路还很长。

6. His home was a small house, one of a long row of similar ones.
    他住在一所小房子里，是一长排样式相同的房子中的一所。

7. He was eating an apple, giving a long melodious whoop at intervals, followed by a deep-toned ding-dong-dong, ding-dong-dong, for he was personating a steamboat.
    他在吃苹果，不时发出长长的悦耳的呼叫声，紧接着是音色深厚的叮咚咚、叮咚咚声，他正在扮一艘轮船。

8. How shortsighted in the long run.
    从长远角度来看，他们的目光是何等的短浅！

9. However, that state didn't last long.
    然而这种情况没持续多久。

10. Home schooling could change children's relations with their peers and older people because of long periods spent with their parents.
    家庭学校可能改变孩子们与同龄人和大人的关系，因为孩子和家长待在一起的时间很长。