Which of the following phonetic transcriptions is right for the “cold”?
A:/kold/
B:/kəud/
C:/kod/
D:/kəuld/
南北半球的分界线为( )
The Shenzhou IX spacecraft returned to the earth safely _______ June 29th, 2012.
用分子的知识解释下列现象,正确的是( )