— So many problems! I'm too tired.— You should try to _____________ them by yourself. You're not a child any longer.
化学与人类的生产、生活息息相关.下列说法不正确的是( )
两个力的合力F为60N,其中一个力F1的大小为20N,那么另一力F2的大小可能是( )