Looking on the internet deeply has found these results:

I thought he might be busy is the most popular phrase on the web.

I thought he could be busy 11 results on the web	I thought he might be busy 122 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
That was surprise because I thought he could be busy, but he made his time for me! I really appreciated that! Genta is my friend from United States, and we had ...	I laughed and told him I thought he might be busy, given we had qualifying races that morning. He replied that we are a team and, if one teammate needs help, ... I walked by his office one day and the door was open and I didn't speak as I thought he might be busy. He was not to busy to call me back and ask why I didn't ... I thought he might be busy because of the holidays but had my husband call him from a different phone. He answered and my husband started to make ... Sep 14, 2015 ... At first I thought he might be busy with the organization branching out into CSGO and HoTS but seems both those teams disbanded already.

I thought he could be busy

11 results on the web

I thought he might be busy

122 results on the web

More popular!

That was surprise because I thought he could be busy, but he made his time for me! I really appreciated that! Genta is my friend from United States, and we had ...

I laughed and told him I thought he might be busy, given we had qualifying races that morning. He replied that we are a team and, if one teammate needs help, ...
I walked by his office one day and the door was open and I didn't speak as I thought he might be busy. He was not to busy to call me back and ask why I didn't ...
I thought he might be busy because of the holidays but had my husband call him from a different phone. He answered and my husband started to make ...
Sep 14, 2015 ... At first I thought he might be busy with the organization branching out into CSGO and HoTS but seems both those teams disbanded already.