It's your turn to be on duty（） A、so it is B、so am I

It's your turn to be on duty（） A、so it is B、so am I it is your turn to be on duty ,为什么用so it is,而不用so i am it is your turn to be on duty.（ ） It’s your turn to be on duty._______ it's your turn to be on duty 不定式在句中做什么成分 It\'s your turn to be on duty这个句子中的动词不定式起什么作用? 英语翻译1.Today I am on duty,it's my turn to clean the classroom whose turn is it-------（be） on duty today it's your duty to deal with the problem.so you can't leave i It is a b---- responsibilily（责任） to be on traffic duty. I find it very important to learn English well.A.So I am B.S it's your turn to do a duty report（改为同义句）