在细胞有丝分裂间期，染色体复制的实质是指[ ]
A．染色体数加倍
B．同源染色体数加倍
C．染色单体数加倍
D．DNA数加倍
答案：D
Only after one has become a parent _____ how great his parents are．
A．he will realize
B．will he realize
C．that he realizes
D．he does realize
在客户生命周期的（）企业投入较少，客户对企业的贡献较大，企业处于高盈利时期。
A.考察期
B.形成期
C.稳定期
D.退化期
