1,who (has/have) a watch?2,who (is/are) they?

1.Who has a watch?
2.Who are they?
取决于who所指的名词是单数还是复数：如
who are you?
who is he?
who am
who is coming to dinner tonight?晚上谁来吃晚饭?
who are coming to dinner tonight?晚上都谁来吃晚饭?
如果所致名词不清楚时,用但单数.
特殊疑问词作主语
who is coming to dinner tonight?
特殊疑问词作宾语
who did you invite to dinner tonight?
就是看who在句子中的语法成分就可以了

1.has
2.are

1 has
2 are
1 当不确定数量时用is
2 由 they 可知应该用复数