题干
— Who's that man in our classroom? It ________ be Mr. Brown. He is much taller.
— You mean the man in white? He is an exchange student from England.
A：can
B：may
C：can't
D：mustn't
答案(点此获取答案解析）
C
C（g）＋D（g）,5 min后达到平衡．已知该温度下其平衡常数K＝1，若温度不变时将容器的体积扩大为原来的10倍，A的转化率不发生变化，则 （ ）