一种病毒的直径约为0.000043m，0.000043m用科学记数法表示为（　　）

A．4.3×10^-4m

B．4.3×10^-5m

C．43×10^-5m

D．0.43×10^-4m

根据句意和汉语提示写出单词，完成句子。

小题1:My father’s ___________birthday is coming ,I will buy him a present . (四十九)

小题2:There is a long river _______________ our city. (穿过)

小题3:He is a teacher and his sister is a _________. (警察)

小题4:When I heard the bad news, I felt even _________. (伤心)

小题5:During the Spring Festival ,all of us have good __________. (心情)