1. Of the two (boys), Long (is) (the best) (at) English
the best -> better
2. (During) his trip to VN, John (enjoyed) (seeing) the boys (to fly) the kites
to fly -> flying
3. I am very (interested) in the (poems) (writting) (by) Xuan Dieu
writting -> written
4. She (studies) hard (in order to) (having) good (mark)
having -> have