you your homework last night?
A:Do; do
B:Were; do
C:Did; do
D:Did; did
下列各组划线词语中注音有误的一项是( )
PM2.5是指大气中直径小于或等于2.5 μm的颗粒物,也称为可入肺颗粒物。大城市PM2.5主要来自汽车尾气排放。会加剧PM2.5污染的因素有( )