选出不同类的单词
A:drive
B:work
C:teach
D:writer
Hearing the good news that he had been admitted into his dream university after so many years of hard work, his parents couldn't help b____ into tears.
人体细胞要获得氧气,排出二氧化碳,必须经过如下①②③等过程来完成
在这些过程中,发生气体交换的有( )