4. －Could I ask you a rather personal question?
－________.
A. Yes, don’t worry B. Of course, go ahead
C. Yes, help yourself D. Of course, why not
3. He ______ on the bed_____ to his parents that blackbirds had_____ their eggs on Mars.
A. lay; lying; lied B. lied; lied; lied
C. laid; laid; laid D lying; lied; laid
2. Children’s curiosity may _____________ many useful inventions.
A. lead to B. take place C. gather in D. bring away
1. ―I want to know if I smoke here.
―No, you .Could you see the sign “NO SMOKING” there?
A. can; needn’t B. must; can’t C. shall; won’t D. may; mustn’t
Sn最大,最大值为S84=2108.4------------------------------10分
本资料由《七彩教育网》www.7caiedu.cn 提供！
当n取接近于的自然数时,即n=84时,
方法二:Sn=50n+=-0.3(n-)2+-------------------8分
所以(Sn)max=S84=50×84+=2108.4----------------------10分
方法一:因为d=-0.6<0, a1=50>0, a84>0 a85<0 --------------------------8分
∴n> ∵n∈N*---------------------------------5分
∴当n≥85时, an<0
即从第85项开始以后各项都有an<0 ------------------------------6分
(2)(满分4分)
