if的用法是什么，当解释为是否时用什么时态

Question

如题所述

Answer 1

if作为从属连接词，有两种用法。
一、做“是否”解释，引导动词的宾语从句，后跟陈述句的语序，相当于一般疑问句。它引导的句子，按照时间来选择时态。如：
He asked if I had left with you, and I said no.
他问我是否和你一块儿离开的，我说不是。
I wonder if I might have a word with Mr Abbot.
请问我能否和阿博特先生说几句话？
二、做“如果”解释，引导条件状语从句，从句中用一般现在时表示将来的含义，主句用将来时，也叫做主将从现，如：
She gets very upset if I exclude her from anything.
要是有什么事情我不让她参加,她会非常难过。
You'll feel a lot better about yourself if you work on solutions to your upsetting situations.
如果你设法找到解决自己麻烦的办法，你自我感觉会好得多。

Answer 2

if,可引导条件状语从句,用为“如果”,时态遵守主将从现.还可引导宾语从句,译为“是否”,从句时态与主句保持一致.本回答被网友采纳

Answer 3

1.(表示条件)如果 ,主句用将来时,if从句用现在时表示将来
He will come if you invite him.
如果你请他,他会来的.
2.(表示虚拟)假如,要是
1）时态：可以表示过去,现在和将来的情况.它的基本特点是时态退后.
a.同现在事实相反的假设.
句型 ：条件从句 主句
一般过去时 should( would) +动词原形
If they were here,they would help you.
b.表示于过去事实相反的假设.
句型：条件从句 主句
过去完成时 should(would) have+ 过去分词
If she had worked harder,she would have succeeded.
The rice would not have been burnt if you had been more careful.
If my lawyer had been here last Saturday,he would have prevented me from going.
If he had come yesterday,I should / would have told him about it.
含义：He did not come yesterday,so I did not tell him about it.
If he had not been ill and missed many classes,he would have made greater progress.
含义：He was ill and missed many lessons,so he did not make greater progress.
c.表示对将来的假想
句型：条件从句 主句
一般过去时 should+ 动词原形
were+ 不定式 would + 动词原形
should+ 动词原形
If you succeeded,everything would be all right.
If you should succeed,everything would be all right.
If you were to succeed,everything would be all right.
3.是否 = whether 连接宾语从句
I wonder if she is ill.
不知她是否病了.本回答被网友采纳

Answer 4

if的用法是什么
What is the use of if

Answer 5

64、芙蓉楼送辛渐 王昌龄