when it comes to后面为什么不能加句子?
后面明显不能加句子，when it comes to中to是个介词不可能再加一个句子
when it comes to用法：
1.可加动名词 doing 或名词，因为这个 to 是介词。
例句：
When it comes to dancing,I'm all thumbs.
谈到跳舞，我真是一窍不通。
When it comes to art,I almost know nothing.
一谈到艺术，我几乎一无所知。
2.when前面可以用逗号，整个跟着某个句子句子后面（用法有点像插入语）。也可以作为分句直接位于句首，整个部分后接逗号。
扩展资料：
to的用法：
1.表示相对，针对
2.表示对比，比较
3.表示修饰关系
4.to还具有依据,伴随,和着节奏的含义，
5.表示相关联，相连接
6.表示反对和赞同。
7.to引导的表示反对，抗拒，对抗意义的词组。
例句：These buildings are resistant to earthquake.
8.to引导的表示同意，赞同意义的词组：consent to,subseribe to,
例句：The employer consented to give him a salary raise.
9.表示调整，使符合，使适应的含义
例句：She tried to habituate herself to the style of plain living.
10.表示投降,屈服,服从的含义
例句：The minority is subordinate to the majority少数服从多数
11.表示趋势或倾向,
例句：He’s liable to seasickness.
12.表示对事情的坚持与执着,
例句：He still holds on to his original views.
13. 表示约束,局限,
例句:He’s confined to the house by illness.
He confined his remarks to scientific mangement.
14. 表示一种习惯或是一种适应性,
例句:Finally,the students got used to my teaching method.
15.表示起因和原由,
例句：The flight was cancelled due to the thick fog.
The famous artist attributed his success to his wife.
16.表示目的或结果,
例句：I aim to be an excellent college teacher.
His conceit lead to his failure.
These bad condition has given rise to a lot of crises
17.表示命运,注定,
例句:All military adventures by the two super powers are doomed to fail.
18. 表示数量上的积累或增加,
例句:In addition to relief supplies,he also presented with some money.
The annual output of steel amounts to 1200 tons.
19.表示全身心投入的含义,
例句：He is determined to devote all his life to his.
20.表示展望或是回顾,
例句：The church dates back to the 13th century.
21.表示方位概念.
例句：I don’t like wool next to my skin.
22.表示依靠或借助,
例句：He usually appeals to arms to settle the territory dispute.
23.表示有关注,关于
24.表示关注或重视
例句：We should attach primary importance to job training.
25.表示依据或是根据
例句：According to today’s newspaper,the match will be postponed.
