They feel ____(内疚) about not being able to see their son often because they are busy with their work.
关于分子的说法下列正确的是（ ）
一 What if someone calls you when you are out?
一 Well. If anyone calls, tell him I'll come back soon.
“蚁穴溃堤”揭示了生物对环境的影响。（判断对错）
