Miss Zhang,the most beatuiful beautiful teacher,has received many flowers and letter theses days.
was receiving是过去进行时,而句中出现了these day这个时间状语,指“这些天”,所以用现在完成时has received.“the most beatuiful beautiful teacher”是个插入语,所以前后用逗号隔开了.
Our teacher always give us advice.We should follow what they .
句子中出现了always,说明老师总是给我们一些建议,所以用现在时;而what they said是表示过去的建议.