在工作或学习中，我们常会使用到英语否定疑问句，那么什么是否定疑问句？该如何使用呢？
下面一起来学习下名词性从句的用法及定义吧：
1.It’s the first time that……….(从句中用现在完成时)
It was for the first time that………(强调句，对状语for the first time进行强调)
It’s (high) time that……..(从句中用过去时或should do)
2.It’s the same with sb. / So it is with sb.
表示某人也如此(用于前句中既有肯定又有否定或两个不同类的谓语动词)
3. …be about to do / be doing……when…….正要做/正在做……就在那时…….
4.A is twice / three times as +原级+as B A是B的两倍/三倍
A is twice / three times the n. of B. A的…是B的两倍/三倍
A is twice / three times +比较级+than B A比B多两倍/三倍
5.It’s a waste of time / money doing / to do…做……浪费时间/金钱
It’s no use / good doing……… 做……是没有用的
It’s possible / probable / (un) likely that………. 很可能……
It makes great / no sense to do……做某事很有/没意义
6.There’s no use / good doing……. 做……没有用
There’s no sense / point (in) doing…… 做……没有意义
There is no need for sth. / to do……. 没有过必要做……
There is (no) possibility that…………(同位语从句)很可能/没可能……
7.The+比较级……..,the+比较级………越…….., 越…….
注意：前半句为从句，用一般现在时代替将来时;
8.It seems / appears ( to sb. ) that sb…….在某人看来某人……
= Sb.seems / appears to be / to do / to be doing / to have done……..
It seems / looks as if……….好象/似乎……..
9.It (so)happened that sb. ……..某人碰巧……..
= Sb. happened to be / to do / to be doing /to have done…..
10.It is said / thought / believed / hoped / supposed …….that sb………
=Sb. is said to be / to do / to be doing / to have done……….
(注意：这种句型里如带动词hope则不能变成简单句，因为无hopesb. to do结构)
11.It is/ has been +一段时间+since从句(从句中如为延续性动词,则实际表示的意思相反)
Eg:It is two years since he drank.他不喝酒已两年了.
12.…….such…….that…….如此…….以致于(引导结果状语从句)
…….such……..as……像……..的这种……(as为关系代词，引导定语从句，在从句里充当主、宾、表)
13. Do you mind if I do sth.? / Would you mind if I did sth.? 你介意我做……吗?
14.The chance is that……../ (The) Chances are that……….很可能…….
15.Check/ Make sure / See to it / See that……..(从句中常用一般现在时) 确信/务必……..
16.depend on it that……..取决于
see to it that…….负责/设法做到…….
注意：除了except / but / in等介词可以直接接that从句，其它介词后必须用it做形式宾语;
17.It is/ was +介词短语/ 从句/ 名词/代词等+that………
How /When / Where / Why is / was it that………..?
注意：此句型为强调句，当被强调的为表示人的词时，还可用who连接;强调主语时，从句后的谓语动词应与前面的主语保持一致;注意与定语从句的区别)
好了，以上的语法知识同学们了解得如何呢？在日常的生活或学习中尽可能地多运用哦。
