Who's the man _____Ryan just talked with?这里用whom不可以吗?为什么答案是that和/?是有who只能用that吗?那为什么还可以不填?

Who's the man _____Ryan just talked with?这里用whom不可以吗?为什么答案是that和/?是有who只能用that吗?那为什么还可以不填?
Who's the man _____Ryan just talked with?
这里用whom不可以吗?为什么答案是that和/?是有who只能用that吗?那为什么还可以不填?

Who's the man _____Ryan just talked with?这里用whom不可以吗?为什么答案是that和/?是有who只能用that吗?那为什么还可以不填?
1.John tells me that his father has a Parker pen (派克钢笔) and he likes it very much.
像这样的一句话,其中有两名男性,句中的he究竟指谁呢,John还是John's father?
2.题中的空,理论上有下列四种填法：
Who's the man that Ryan just talked with?
Who's the man Ryan just talked with?
Who's the man whom Ryan just talked with?
Who's the man who Ryan just talked with?
很明显,后两个,读起来让人觉得不舒服,因为人称疑问词两次出现.
3.用后两种是不是就一定不行呢?这倒未必.我们在google上搜到了4800个例子,但都是中文网站上的.既然让我们选最佳答案,那我们还是要选that/-.