小升初必備語法：不定式的時態(tài)和語態(tài)

　　一般式　　　　　 to do　　　　　　to be done

　　進(jìn)行式　　　　　 to be doing

　　完成式　　　　　 to have done　　 to have been done

　　完成進(jìn)行式　　　 to have been doing

　　1) 現(xiàn)在時：一般現(xiàn)在時表示的動詞，有時與謂語動詞表示的動作同時發(fā)生，有時發(fā)生在謂語動詞的動作之后。

　　He seems to know this.

　　I hope to see you again. = I hope that I'll see you again.　我希望再見到你。

　　2) 完成時：表示的動作發(fā)生在謂語動詞表示的動作之前。

　　I'm sorry to have given you so much trouble.

　　He seems to have caught a cold.

　　3) 進(jìn)行時： 表示動作正在進(jìn)行，與謂語動詞表示的動作同時發(fā)生。

　　He seems to be eating something.

　　4) 完成進(jìn)行時：

　　She is known to have been wreaking on the problem for many years.