Sir, I think these two are your best, and care not who knows it.

Sir, I think you may need a bit of a reality check.

Sir, I think your question can be answered quite simply.

"Sir, you cannot think that I would try to undermine your work here."

Sir, I think we have no choice but to keep to the problem at hand.

"Sometimes, sir, I think you're a little too good at seeing the other fellow's point of view."

Look, sir, I think you're taking a rather romantic view of this.

Sir, 110 and 111 think they can make it work for us.

Sir, I think you should talk to higher about that.

"No, sir, but I think they were going to get married."