my studen do homework three or four times a week no studen do homework once or twice a week
问题描述:
my studen do homework three or four times a week no studen do homework once or twice a week
答
or可以表示或者和否定句中的否定 and只可以表达成“和”的意思 而句中意思要表达是3次或者4次.所以用or不用and 或者关系而不是并列关系 一