時態\語態 主動 被動
一般式 to doto be done
進行式 to be doing
完成式 to have done to have been done
完成進行式 to have been doing
1) 現在時：一般現在時表示的動詞，有時與謂語動詞表示的動作同時發生，有時發生在謂語動詞的動作之後。
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) 進行時： 表示動作正在進行，與謂語動詞表示的動作同時發生。
he seems to be eating something.
4) 完成進行時：
she is known to have been wreaking on the problem for many years.