Question

I bought the cell phone last week. (改为同义句)

I________ the cell phone since last week.

Answer

have had

【解析】

句意：我上周买的这个手机。(改为同义句) 我从上个星期就开始有这个手机了。

根据since last week可知要用现在完成时，且bought是非延续性动词，现在完成时需要用延续性动词，故将bought改为延续性动词have had。故答案为have had。