The classroom is very dirty.it is hard to clean it和it is har

秃顶高手来了
哈哈,考得就是不定式哈.
its hard to clean ,所谓""反射性不定式"",其实就是to do it is hard .
its hard to do it ,不用.因为上面的更简洁,而且it 还重复了.--用这个会被美国佬笑话的