The computer ______in the shop yesterday.[ ]

A. was bought

B. was buying

C. bought

D. is bought

我们在用紫背天葵“探究扦插材料的处理”时，对实验材料的处理不正确的是[ ]

A．将紫背天葵剪成15-20厘米左右的茎段

B．每个茎段要保留2个节

C．每个茎段上下方切口都要一样

D．进行扦插时茎上要保留部分叶片