人参总皂苷中属于四环三萜皂苷元的皂苷有（）

A．人参皂苷Rb₁

B．人参皂苷Rc

C．人参皂苷Re

D．人参皂苷Ro

E．人参皂苷Rg₁

The native Canadians lived in __________ with nature, for they respected nature as a provider of life.

A．contact

B．contrast

C．harmony

D．relation