他太忙了，或是开会去了，休假去了。。。 职场沟通第一定律：你不问，怎么知道？

和大牛二牛无关，与你想继续合作也无关，做事时积极主动效果最好。

从贴中没看出，为什么对方多次提出开会，但仍未开成的原因。画蛇添足，说一下客气地掌握主动，定时间的方法：

A: Let's get together to talk about it.

B: Great. What time is good for you? My calender is quite free next week so far, any time is good for me. 

A: How about next Monday?

B: Yes. Next Monday (Sep. 15th), 10 am in your office?

A: That sounds good.

B: See you next Monday.