Grades would______from one or two，for outstanding or excellent，to six or seven，for poor or very poor.

A．suffer

B．differ

C．come

D．range

妊娠晚期因增大子宫的压迫和腹压增高，使痔静脉回流受阻和压力增高导致痔静脉曲张，故形成痔疮多见。