【原句】 Indeed, sir, I hope you’ll come here whenever you like.
此句是一个主从复合句，主句是“I hope”，其后是一个省略了连接词that的宾语从句，whenever引导一个时间状语从句。whenever意为“在任何时候，无论何时”，相当于no matter when。
(1) whenever, wherever, however引导让步状语从句，相当于no matter when / where / how。
e.g. However great the difficulty is, we must complete the task in time.
= No matter how great the difficulty is, we must complete the task in time.
(2)whatever, whoever, whichever, whomever既可引导让步状语从句，也可引导名词性从句。引导让步状语从句时，相当于no matter what / who / which / whom。
e.g. Whatever your problems are， you can’t lose heart.
= No matter what your problems are，you can’t lose heart.
引导名词性从句(主语从句和宾语从句 )时，不能用no matter what / who / which / whom 替代。
e.g. ①Whoever comes will be welcome. (主语从句)
②Prisoners have to eat whatever they are given. (宾语从句 )
e.g. ①Will you tell me how you learned English well?
②I think he’ll be back in an hour.
③She said she had done her homework.
④The teacher told us light travels faster than sound.
e.g. Do you know he has joined the army?
(2)如果从句是一般疑问句，用连接词whether / if。
e.g. ①I asked her if she could call me.
②I wonder whether you can change this note for me.
e.g. She did not know what had happened.
a. 许多描述情感的形容词( happy, anxious, glad, afraid, pleased, sorry, proud, surprised, worried, ashamed, surprised等)，或表示确信无疑的形容词(certain，sure等)，后可带宾语从句。
e.g. He was happy that I arrived on time.
e.g. We consider it necessary that he should improve his pronunciation.
c. 当主句谓语动词为think, consider, believe, suppose, expect, fancy, guess, imagine等表示思想和感觉的动词时，其后的宾语从句若含有否定意义，一般要把否定形式转移到主句谓语动词上来，发生否定转移，而从句谓语动词仍用其肯定形式。
e.g. I don’t think this dress fits you well.
表语从句就是指在复合句中作表语的名词性从句。表语从句在复合句中放在系动词之后，一般结构是“主语 + 连系动词 + 表语从句”。
e.g. The trouble is that I have lost his address.
(2)连接词whether, as, as if / though可引导表语从句， whether在表语从句中表示不确定, as表示“正如”, as if / though表示“好像”。
e.g. ①He looked just as he had looked ten years before.
②It looked as if / though it happened yesterday.
(3)连接代词what, who, whom, whoever, whatever, whomever, whose引导表语从句时，既起连接主从句的作用，又在从句中作成分(主语、宾语等)。
e.g. That’s not what I meant.
(4)连接副词how, when, where 引导表语从句既起连接主从句的作用，又在从句中作成分(状语)。
e.g. ①I wondered how he came here.
②He knows where they are.
b.能跟表语从句的谓语动词一般为系动词be, seem, look, appear等。
e.g. ①It seemed that he had worked hard.
②It looks that the Americans will endure a cold winter.
③It appeared that he had an unusual taste for music.
c. 可以接表语从句常用的还有the reason is that, it is because (强调原因) 和that’s why(强调结果) 等结构。
e.g. ①That’s because he didn’t understand me.
②That’s why he got angry with me.