起始进近航段采用直线航线时，保护区的副区在主区两侧，宽度各为总宽度的：（）.
A.1/2
B.1/3
C.1/4
D.1/8
参考答案：C
It ________ quite correct that happiness comes from thinking about things in a positive way. [ ]
A. has turned out
B. has been turned out
C. is turning out
D. is turned out
青蛙的变态发育大约经历多少天[ ]
A．30多天
B．40多天
C．50多天
D．60多天
