A:雨衣
B:食品包装袋
C:手电筒外壳
D:盖大棚蔬菜用的薄膜
它们之间有如下反应关系.
我国古代生产工艺中主要体现物理变化的是 ( )
A. He is sending an email to his friend.
B. This dress is for Amy.
C. The boys are playing football.
D. This girl is writing a letter.
E. We had a happy time in the park.
(____)
(____)