题干
At the beginning of the 20th century
, many people thought that the family was falling apart--- _______, they thought it was dying.
A：on the other hand
B：for another
C：in other word
D：in additio
答案(点此获取答案解析）
C
，到那时太阳向外辐射的能量是由上述两种核反应共同产生．若已知
的质量为m1，
的质量为m2，则下列判断正确的是
