改错,这个句子有错吗?If the teachers speak English without any gesture

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.

错的比较多
首先应该是the students,然后 应该是what the teachers say

... maybe the students will not understand clearly what the teachers are saying.

maybe don’t understand
may not nuderstand