用代词的适当形式填空

小题1:These books are ____ (she).

小题2:___name is Li Lei. (he)

小题3:Thank ___ very much. (you)

小题4:He is in ____room. (us)

小题5:Are ____ Chinese? (he)

小题6:How old is ___? (her)

小题7:Excuse ____.(I) May I use your ruler?

小题8:This is ____ classroom. (we)

小题9:Can ____ spell it, please? (you)

对因瓦斯浓度超过规定被切断电源的电气设备，必须在瓦斯降到¬（）以下时，方可通电开动。

A、1.0%

B、1.5%

C、0.5%