1. announce vt. 宣布; 述说; 声称
例句:Please announce to the children that there will be no school this afternoon.
请通知孩子们今天下午不上课。
2. explore vi.勘查, 探测, 勘探
例句:In this chapter, we explore how and why.
在本章中我们将探讨如何消除和为什么要消除它们。
3. explain vt.讲解,解释
例句:He made up a story to explain why he was absent.
他编造了一个故事为他的缺席辩解。
4. involve vt.包含; 使参与,牵涉
例句:Certainly he wasn't going to involve the other comrades.
他肯定不想带累别的同志。