Question

I am sure ___ for us at the station when we arrive

Answer 1

that ...................

Answer 2

Answer:

The given space can be filled in by: he/she/they will be waiting

So, the sentence will be:

I am sure he will be waiting for us at the station when we arrive.

Or

I am sure she will be waiting for us at the station when we arrive.

Or

I am sure they will be waiting for us at the station when we arrive.

The phrase should be in the future tense as the people mentioned in the context are yet to arrive. Future continuous tense has been used here.