If you still remember the ______ time of the accident, please tell us. We would ______ your help.

A．approximate; appreciation

B．approximately; appreciate

C．approximate; appreciate

D．approximately; appreciation

下列关于₂³He的说法正确的是（　　）

A．₂³He原子核内含有2个中子

B．₂³He原子核内含有3个质子

C．₂³He原子核外有3个电子

D．₂³He和₂⁴He是两种不同的核素