Would you like some sugar?
砂糖はいかがですか?
Would you like some water?
お水はいかがですか?
Would you like some coffee?
コーヒーはいかがですか?
Would you like to have lunch with me?
一緒にランチはいかがですか?
Would you like to come with me?
私と一緒に来てはどうですか?
Would you like me to wash the dishes?
私がお皿を洗うというのはどうですか?