现在进行时和过去式的区分.高手进
有几道题不太懂,麻烦讲解一下.
1.The thief（ ）in from the kitchen window as all the other windows and doors were closed
A.may climb B.must have climbed C.could climb D.should have climbed
2.I am sorry to keep you （ ）for a while ,for there is no chair .
A. stand B.standing C.stoodD .to stand
3.We saw him （ ）off the tree two days ago.
A.fell B.fall C.to fall D.faided
4.She （ ） （not play ） football these days .
5.How long （ ）your uncle （ ）（live）in Beijing.
请详细解答.谢谢~~~
另外.如何区分过去式和现在进行时,不要像是课本的.越通俗易懂越好
谢谢,可另给分.
额错了 ~~~是现在完成时...