休克
A．肺性发绀B．心性混合发绀C．淤血性发绀D．缺血性发绀E．混合性发绀
参考答案：D
—Did you _____ the Dragon Tower?
—Yes, I _____ it was the tallest steel tower in Asia. [ ]
A. hear, hear about
B. hear about, heard that
C. heard about, hear
到1992年为止，人类已发现了多少种化学元素( )。
A．106
B．119
C．112
D．128
