Tim has parked his car next to a white car before he went to sleep改错
问题描述：
Tim has parked his car next to a white car before he went to sleep改错
Those workers are recycling building material改错
答
Tim had parked his car next to a white car before he went to sleep ( has -> had 因为动作发生在WENT 之前）Those workers are recycling building materials ( material -> materials )