选A.在这个句中work out 中的out是副词,当宾语是代词时,要放在out前面,宾语是名词时,放在out前面或者后面都可以.如:work out the problem=work the problem out 再如:put on your coat=put your coat on,但需要用put it on.不可以用put on it. 类似的还有:turn on,turn off,take off 等.
选A。在这个句中work out 中的out是副词,当宾语是代词时,要放在out前面,宾语是名词时,放在out前面或者后面都可以。如:work out the problem=work the problem out 再如:put on your coat=put your coat on, 但需要用put it on. 不可以用put on