电源电动势为ε，内阻为r，向可变电阻R供电.关于路端电压，下列说法中正确的是 （ ）

A．因为电源电动势不变，所以路端电压也不变

B．因为U=IR，所以当R增大时，路端电压也增大

C．因为U=IR，所以当I增大时，路端电压也增大

D．因为U=ε-Ir，所以当R减小时，I增大时，路端电压下降

根据句意，在答卷标有题号的横线上，写出括号内所给单词的适当形式。

小题1:How strange he is! Maybe he is the __________ (mad) man I have ever seen.

小题2:The manager asked if the message on the desk was for one of the _________ (salesman).

小题3:After school all the students went out of the classroom __________ (noise).

小题4:The man in his __________ (forty) is the person who saved that boy.