下列IP地址中()是C类地址。
A.127.233.13.34
B.152.87.209.51
C.169.196.30.54
D.202.96.209.21
参考答案:D
----How did you find your first visit to Heilongtan Lake?
-----_______.
A.taking a bus.
B.Oh, wonderful, indeed.
C.I went there alone.
D.A classmate of mine showed me the way
关于催化剂的说法正确的是( )
A.催化剂只能加快化学反应速率
B.催化剂在化学反应前后其质量和化学性质不变
C.催化剂可增加生成物的量
D.MnO2可作任一反应的催化剂