质量为50kg的钢制零件皮装在飞机上使用。装上零件后飞机超重100N。为减轻机重，设计师将50kg的钢制零件部分改为铝制零件，问至少需要多少kg的铝代替钢件才能保证飞机的超重？（ρ_铝=2.7×10³kg/m³，ρ_钢=7.9×10³kg/m³，取g=10N/kg）

用括号内所给动词的正确形式填空：（10分）

小题1:When ________ Luoshe Middle School __________ (set up)?  ---In 1940. 

小题2:I was made ________ (perform) the dialogue once more by Miss Chen.

小题3:Dr. Zhang like other volunteers ________ (train) the local doctors and nurses when we went to visit him. 

小题4:---How do you like our city?

---Wonderful. I _________ (stay) here for two more days.

小题5:Any book in the library mustn’t ___________ (take) away.

小题6:A fridge is used _________ (keep) food flesh.  

小题7:Doctors should pay more attention to _________ (operate) on the ill people.

小题8:Adults always told children the sun _________ (rise) in the east when they were young.  

小题9:If it __________ (not be) rainy tomorrow, we will have a trip to Yangshan.

小题10: ________ the police ________ (group) themselves into a team of nine since they started to work?