A:①②③
B:①③④
C:①②④
D:②③④
下列四组连线中,完全正确的是( )
圆柱的底面直径和高都扩大到原来的2倍,则它的侧面积、底面积分别都扩大到原来的()倍。
关于光学器材或设备,下列说法错误的是( )
— When's your birthday?
— It's ___________ January 1st.
— What would you like ________ a birthday present?
— I would like a yo-yo. ( )