生石灰的化学成分是( )。
A．CaCO3
B．CaO
C．CaC2
D．Ca(O2
参考答案：A
与a相邻的两个整数a-1与a+1，这三个数之和为120，这三个数分别是______，______，______．
The teacher together with the students ________ discussing Reading Skills that ________ newly published in America.
A．are；were
B．is；were
C．are；was
D．is；was
