复数(1+i)3的虚部为( )
A.-2
B.2
C.2i
D.-2i
(1+i)3=(1+i)2(1+i)=2i(1+i)=-2+2i,
故选B.
Water is (41) important of all the things we (42) and drink. Not many people understand this, (43) it’s quite true. The human body (人体) can go (44) food for a long time, but two (45) three days without water can usually (46) people die. Many people don’ t understand how much water the human body needs to work well and many people do not drink (47) , even (48) hot weather. Our body is (49) water, about 65% to 75%, ff we do not have enough water, we’ll (50) tired and many will get ill. So you see, how important water is to us all.
[A] and [B] but [C] because
作业的灵活性反映系统应付用户异常需求变化的能力,如增减数量、改变到货地点等。()