已知一元二次方程x2-4x+3=0两根为x1、x2, 则x1·x2= ( ).
- I don't know Kate's address. Do you know _______?
- Sorry, I don't know, either.
下列有关加酶洗衣粉及其洗涤效果的叙述中,错误的是( )
人体内主要的呼吸肌是( )