根据句意，用括号里所给词的适当形式填空。

小题1:____________ (luck), I passed the examination.

小题2:His illness is even          (bad) than I thought it would be.

小题3:—Jim’s sister and her husband are a happy couple.

—When did they get _____________(marry).

小题4:Lin Tao would like to go somewhere __________ (relax).

小题5:Watch __________(care), and you will find the differences between the two pictures.

什么叫水泵串联？串联的目的是什么？