we all know it's difficult to p _______everybody

we all know it's difficult to p _______everybody We all know we have only one earth to live o__.It's our duty It's difficult to get to know a reserved people I know it's difficult to do that. We all know __________（污染） air does harm to our health.It’s 1We all know it's ____ to eat in class we all know it 's useful ______English well.为什么是to learn ,有什 As we all know ,it’s not polite to keep others_for a long ti we all know that —can be used to make mang things ,so it's o We know it's easy to ( )him as we all know it It's difficult to choose!