substitute test与alternative test有什么区别

span name=whlm id=whlmexamine 是检查是否出了毛病的意思相当于to see if there is something a href=
check 是核实,核对的意思,相当于to see if it is right or not eg.Look at the sentence on the blackboard and check your own answers.
test是检测 调试的意思,相当于 to see if it can work or to meet the need eg.Before a plane is put into service,it should be tested first