Your English is very good中为什么要加is

Your English is very good中为什么要加is Your English is very good!( ). Your English is very good怎样回答 Your English is very good该怎样回答 Your(speak)English is very good oh your english is very good English is very good? your english is good Your English is very good. Are you from England? learning English is very interesting 为什么learn要加ing 1.his speaken English is excellent中is后为什么不可以加very? your picyure is very good