Mr Smith is come from america,so is helen.哪错了,为什么?

Mr Smith is come from america,so is helen.哪错了,为什么?

应该是comes from或者直接is from
哪有be动词后面还跟动词原形的

Mr Smith is from america, so is helen.这样说才是对的.
Mr Smith comes from america, so does helen.这样说也是对的.
请仔细注意不同之处。