问个英语问题用动词适当形式填空 This kind of glasses (be)used to protect eye

问个英语问题
用动词适当形式填空
This kind of glasses (be)used to protect eyes.
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一些“成双成套”的名词,如 trousers /pants /glasses /clothes /shoes /scissors/compasses(圆规)等用作主语时,谓语动词常用复数;若此类名词前有a (the/this) pair of /a suit of等量词修饰时,谓语动词则常用单数形式.
My glasses are broken.I have to buy a new pair.
The pair of shoes under the bed belongs to Tom.
a kind (或sort,type,series) of + 名词”作主语时,其谓语动词要用单数形式,如：
A series of his works has been printed.
There is a kind of rose in the garden which fills the air with fragrance when May comes.
注①：在“this kind of + 名词”结构中,不管名词是单数还是复数,谓语动词都用单数形式,如：
This kind of man annoys me.
This kind of men is dangerous.
This kind of apples is highly priced.
This kind of book(s) is useful to us.
注②：在“these / those kind of + 复数名词”结构中,谓语动词则用复数,（kind of前后的词均为复数）,如：
These kind of tests are good.
These kind of cars are made in Japan.
These type of machines are up-to-date.
These kind of men annoy me.
注③：kind本身为复数,谓语动词也应当用复数形式,如：
Some kinds of bamboo grow very fast.
There are many kinds of apples.
Those kinds of apple trees have not yet grown up.
There are different kinds of animals in the zoo.
注④：如果以apples / men 作名词词组的中心词,谓语动词自然也用复数,如：
Apples of this kind are highly priced.
Books of this kind are useful to us.
Men of this kind are dangerous.
Films of this kind are not worth seeing.
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