修改病句英语的my brother bought aumbrella.there is cloud in the sky

第一句是冠词使用错了.umbrella雨伞,一把雨伞,冠词应该用an,所以这句改为：
My brother bought an umbrella.
第二个句子是缺少冠词,there is 单数句,cloud 前面应该加a.所以这句改为：
There is a cloud in the sky.
第三个句子是多了冠词,How many是问多少个,应该用名词复数,不能用a,所以这句改为：
How many apples are there?
理解请采纳,不明白可再问,