若二项式(x+2)n的展开式的第四项是42,而第三项的二项式系数是14,则x的值

题型:选择题

问题:

若二项式(x+2)n的展开式的第四项是
4
2
,而第三项的二项式系数是14,则x的值为(  )
A.
1
2
B.
1
4
C.
2
8
D.
1
8
考点:二项式定理与性质
题型:选择题

阅读理解

       Li Ping is a Young Pioneer (少先队员). He goes to the wildlife park (野生动物园). When he waits

for a bus at the bus stop, he finds a watch on the road (马路). He asks some people, "Whose watch is it?" But the watch isn't theirs. So he gives it to the policeman.

       Li Ping gets on the bus. There are many people in it. Li Ping sits near the door. An old man gets on

the bus, too. He has no seat (座位).So Li Ping stands up and says: "Here is a seat for you. Grandpa,

please sit here."

根据短文,正确的写T,错误的写F。

( )1. Li Ping finds a watch on the road and gives it to an old man.

( )2. Li Ping goes to the wildlife park by bus.

( )3. There're many people in the bus.

( )4. Li Ping takes the old man's seat.

题型:选择题

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B.潮汐节律行为

C.季节节律行为

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