英语词组不少是由动词+介词构成的,如：look after,think about; 这类动词短语后直接接宾语,如：
Her job is to look after children in the nursery.
They have a baby,and they look after her carefully.
They will think about the problem before they make the decision..
The problem is vital,and they are thinking about it seriously.
也有不少是英语词组由动词+副词构成的,如：add up,think over; 这类动词短语后接接宾语时,有两种情况,1.宾语是名词时,这个名词可以放在短语后,也可以放在短语中间；2.宾语是代词时,这个代词可就只能放在短语中间.如：
The teachers told the kids how to add up numbers.
The teachers told the kids how to add numbers up.
The teacher wrote some numbers on the blackboard and asked the kids to add them up.
They will think over the problem before they make the decision..
The problem is vital,and they are thinking it over.
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