乘法

Acridine orange dyeing was used to observe the proliferation of cell in collagen sponge at 20 and 35 days of culture.

培养20，35 d，对共培养物进行AO染色，观察细胞在胶原海绵中的增殖情况。

It is an oft repeated axiom that money cannot buy happiness.

这是一个经常反复公理说，金钱不能买到幸福。