The Mekong River, which________ severalcountries in Southeast Asia, ______to be playing a significant role in the region.

I don’t doubt ____________ she can do it well, but Idoubt _________ she is willing to do it.

What do you guess our friend Bob when we get to his home?

When I was at a loss, the thought of traveling abroad did _____ to me.

Please don’t get too close to the building______ roof is under repair.