1.可以.it's hot,it's cold,it's warm,it's rainy,it's cloudy,it's sunny 都很常用
2.不一定.大部分时间放在开头,但也可以将what开头的句子放进另一个句子当中：
do you know what the answer is?你知道答案吗?
does the teacher know what the answer is?老师知道答案吗?
3.beauty是名次,表示美人或美丽的东西.
That girl is a beauty.那个女孩儿是个没人
beautiful 是形容词,形容某件东西或某人很美丽,漂亮.
That song was beautiful.那首歌很动听（美丽）.
She is beautiful.她很漂亮.