例句：As I look back at the world I left, it is all so clear to me.
我回头看着身后的世界，一切是如此清晰。

2.by that time 到那时；到那个时候；等到那时候

例句：There seemed no obstacle to arresting Mr Mladic, but by that time the authorities appeared to have lost track of him.
这样看起来逮捕姆拉迪奇似乎没有什么困难了，但是在那个时候权力机关却失去了他的行踪。

3.take a few tentative steps 小心翼翼地迈开步子

例句：We push ourselves up, we take a few tentative steps, then we fall down.
我们先抬起双脚，小心翼翼的迈开步子却又接着跌倒。

4.samples of ...的样品

例句：The bacterial endotoxin tests of 3 batches of samples were all up to the standards.
3批样品细菌内毒素检查均符合规定。