试比较：
Your hand feels cold.（无意识的静态性质。）你的手摸起来冰凉。
不可以说：
Your hand is feeling cold.(×)
但可以说：
The doctor is feeling her pulse.（有意识的动态动作）医生正在给她拿脉。
The soup tastes good.（静态性质，无进行时）这汤的味道不错。
The cook is tasting the soup.（动态动作，有进行时）厨师在尝汤的味道。

总之，系动词有无进行时态应随系动词的意义或其语境变化而变化。
我们在概述某一动词的进行时态时，不能笼统地说feel，smell无进行时，应指出其意义及其语用环境。
例如smell的用法可见一斑。
①smell作“嗅觉”的能力时，虽是实义动词，但指的是一种性质的存在状态不能用于进行时态，常与can, could, be able to连用。
The camels can smell the water a mile off.骆驼能嗅出一英里外有水。
②指“嗅、闻”的动作时，实义动词，可用于进行时态。
The girl is smelling the flower.这姑娘正在闻那朵花。
③smell指“含有……气味”，“发出……气味”等事物性质时，半系动词，无进行时态。
The dinner smells good.这饭菜闻起来真香。

2．系动词的时态与形容词的比较级连用的问题。
某些含有变化意义的动态系动词如get, become, grow, turn等的进行时态可与形容词的比较级连用，表示渐进过程，其意思是“越来越……”。例如：
He is growing taller and taller.他长得越来越高了。
Our life is getting better and better.我们的生活是越来越好了。
The things are getting worse.情况是越来越糟了。

3．所有半系动词的被动语态要分情况讨论。
英语中某动词在作系动词用时，无被动语态，而作实义动词用时，才有被动语态，二者不可混为一谈。例如：
不能说：
The apple is tasted good.
（因为taste此时是系动词，“尝起来”之意，指的是苹果的性质，无被动语态）
但我们可以说：
The apple is tasted by me.这苹果被我尝了一下。
（taste此时指“尝一尝”这一动作，有被动语态）
因此，在平时的英语教学和学习之 ，要有意注意半系动词在具体的语言环境中到底是系动词用法还是实义动词用法，要注意区分、识别。

4．瞬间动态系动词能否与时间段连用的问题
英语中某些表示瞬间意义的系动词不能与“for+时间段，since+时间点，how long until+时间,by + 时间，so far”等直接连用。例如：
①不能说：He has become a teacher for 2 years.
应改为：He has been a teacher for 2 years.
②不能说：He has turned writer since 3 years ago.
应改为：He has been a writer since 3 years ago.
或It is three years since he turned writer.
③不能说：He got angry until his child came back home.
应改为：He didn’t get angry until his child came back home.

5．系动词能接几种表语（从句）
系动词除了接adj.\n.\prep.短语，某些adv.以外，还可接以下几种表语形式：
①能接as if/as though表语从句的系动词有：look（看起来），smell（闻起来），sound（听起来），feel（觉得）；appear（显得），seem（似乎）。例如：
It looks as if we are going to have snow.看样子天要下雪了。
He looked as if he had just stepped out of my book of fairy tales.
他看来好像刚从我的童话故事中走出来似的。
She seemed as if (though) she couldn’t understand why Laura was there.
看来她好像不能理解为什么劳拉呆在那儿。
It sounds to me as though there’s a tap running somewhere.
我好像听到某处水龙头流水的声音。
She felt as if her head were splitting.
她仿佛觉得她的头要裂开了。
The river appeared as if enveloped in smog.
那条河好像笼罩在烟雾之中。
It seems as if it were spring already.
好像已是春天了。
②可用于“It+系动词+that从句”结构的有：seem, appear, 不可用be, look。如：
It seemed that he had made some serious mistakes in his work.
好像他在工作中犯了严重错误。
It appeared that he was talking to himself.
好像他在自言自语。
③能用不定式作表语的系动词有：be, seem, get, look, appear, prove, grow.
Her job is to look after the children.
她的工作是照料孩子们。
He seems not to look after the children.
他好像不是她的父亲。
She looks to be a young girl of twenty year-old.
她看起来像是一个20岁的年轻姑娘。
He didn’t appear to dislike it.
看不出他憎恨此事。
My advice proved to be wrong.
我的建议证明是错误的。
He will grow to like this work gradually.
他会逐渐喜欢这个工作的。
④能与there连用的系动词有：be, appear, seem.
There appeared to be only one room.
那儿好像只有一个房间。
There seems(to be)no need to go.
似乎没有必要走。

6．能用两种否定形式的系动词有两个：seem, appear.
举例说明：
It doesn’t seem that we can get our money back.= It seems that we can’t get our money back.
He seems not to be her father.= He doesn’t seem to be her father.
The baby doesn’t appear to be awake.= The baby appears not to be awake.

7．后接作表语的过去分词可构成系表结构
能构成系表结构的系动词通常有两个：第一个是常见的be(is, am, was等)；第二个是get，口语中常用。
当二者作系动词用时，它们均表示一种存在状态，而不表示被动动作；当二者作助动词用时，后接作谓语的过去分词构成被动语态。
Be + P.P常可以用get + P.P.来代替，但是并不是be系动词总是可以用get来代替。Get + P.P.系表结构常用于以下两种情况：
1）表示偶然的、突发性的、意想不到的被动动作的结果或状态。
Last night I got caught in the downpour.昨夜我被雨淋了（表示意想不到）
The new car got scratched.新车给刮坏了。（表突发性）
2）表示对自身所作的事。如get dressed, get lost等。
John got injured while playing football last Saturday.约翰上周星期六踢足球时受了伤。
They got married last month.他们上个月结婚了。
另外，要注意区分系表结构与被动语态结构的用法。