A:①②③④
B:①②③
C:②③④
D:①③④
在相同时刻太阳光线是平行的,如果高1.5米的测杆影长3米,那么此时影长30米的旗杆的高度为( )
在数列{an}中,a1=2,2an+1=2an+1,则a101的值为 ( )
— Would you like to go for a picnic with me?
— ______ I have to help Kate with her Chinese