コーヒーを１杯いかがですか。
    Will you have a cup of coffee? 
    Won't you have a cup of coffee? 
    Would you like a cup of coffee?
　  How about a cup of coffee?     
コーヒーを１杯いただけますか。
　　May I have a cup of coffee?
　　Can I have a cup of coffee?
　　Please give me a cup of coffee.
　　I would like to have a cup of coffee.