_______ basic first-aid techniques will help you respond quickly to emergencies.

A．Known

B．Having known

C．Knowing

D．Being known

证券收益性的多少通常取决于( )。

A．资产增值数额的多少

B．该证券的需求状况

C．证券市场的供求状况

D．证券发行时间的长短