IF

1. (表示條件)如果

He will come if you invite him.

如果你請他，他會來的。

2. (表示虛擬)假如，要是

If I were you, I would never do that.

如果我是你，我決不做那件事。

3. (表示讓步)即使

We'll go even if it rains.

即使下雨我們也要去。

4. 是否

I wonder if she is ill.

不知她是否病了。

5. (表示因果關係)每一次...的時候(總是會)

If I feel any doubt, I inquire.

我一感到有疑問就隨時詢問。

• n. 條件；設想

There are too many ifs in his offer.

他的提議中條件太多了。

IF=i.f.

if.

縮寫詞 abbr.

1. =information feedback 信息回饋

2. =interferon

3. =intermediate frequency 中頻

1. if和whether在賓語從句中，都表“是否”，可換用，if更口語化，whether正式些。

當有or not時，一般用whether，而不用if。

He wants to know if/whether you can help him.

She wonders whether you'll go or not.

2. if可引起條件狀語從句，whether不用於狀語從句。

If you work hard, you'll succeed.

If I were you , I would do it in another way.

3. whether可引起主語從句，表語從句，if不能用於這兩種情況。

Whether you can finish it in time or not depends on yourself.

The question is whether they'll help you.

4. if在名詞性從句中只能引導動詞后的賓語，whether可通用。

依據《柯林斯英漢雙解大詞典》，意為：

1.CONJ You use if in conditional sentences to introduce the circumstances in which an event or situation might happen, might be happening, or might have happened. (引導條件從句) 如果

2. CONJ You use if in indirect questions where the answer is either "yes" or "no." (用於間接是非問句中) 是否

3. CONJ You use if to suggest that something might be slightly different from what you are stating in the main part of the sentence, for example, that there might be slightly more or less of a particular quality. (表示與主句所述事實可能有少許不同) 即使

4. CONJ You use if, usually with "can," "could," "may," or "might," in a conversation when you are politely trying to make a point, change the subject, or interrupt another speaker. 常與(can)、(could)、(may)、(might)等情態動詞連用，表示婉轉客氣

5. CONJ You use if at or near the beginning of a clause when politely asking someone to do something. (用於從句句首或靠近句首的位置，表示禮貌的請求) 是否 [禮貌]

6. PHRASE You use if not in front of a word or phrase to indicate that your statement does not apply to that word or phrase, but to something closely related to it that you also mention. 即便不

7. CONJ You use if to introduce a subordinate clause in which you admit a fact that you regard as less important than the statement in the main clause. (引導從句，提出次要的事實) 即使

8. PHRASE You use if ever with past tenses when you are introducing a description of a person or thing, to emphasize how appropriate it is. (與過去式連用，強調對人或事物的描述極為恰當) 如果有…的話 [強調]

9. PHRASE You use if only with past tenses to introduce what you think is a fairly good reason for doing something, although you realize it may not be a very good one. 即使僅僅 (與過去式連用，引出能勉強說明做某事的原因)

10. PHRASE You use if only to express a wish or desire, especially one that cannot be fulfilled. (尤指不能實現的願望) 要是…多好 [情感]

11. PHRASE You use as if when you are making a judgment about something that you see or notice. Your belief or impression might be correct, or it might be wrong. (表示判斷) 好像

12. PHRASE You use as if to describe something or someone by comparing them with another thing or person. (表示類比) 彷彿

13. PHRASE You use as if to emphasize that something is not true. (強調某事不是真的) 好像…一樣 [口語]

if any若有的話 ; 即便要 ; 如果有 ; 如果有的話

if at間接熒光抗體試驗 ; 德國慕尼黑國際環博會 ; 間接免疫熒光法 ; 間接免疫熒光試驗

Hammarby IF哈馬比 ; 哈馬比足球俱樂部 ; 哈馬爾比