改错,这个句子有错吗?

题目

改错,这个句子有错吗?
If the teachers speak English without any gestures,objects,pictures and so on at first when they have a new lesson,the student maybe don’t understand clearly what the teachers said

答案

If (the) teachers speak (in) English without any gestures,objects,pictures and so on at (first->beginning) when they (have->give) a new lesson,(the) student (maybe don’t -> may not) understand clearly what the teachers (said -> say or are saying).
Right one:
If teachers speak in English without any gestures,objects,pictures,and so on at beginning when they give a new lesson,students may not understand clearly what the teachers are saying.