The oil wells will all run dry in _____ thirty years at the present speed of use[ ]

There are severalfactors _______ in the economy _______ make it difficult to predict the future

_____, I think the show is going to be a great success though many people don’t think highly of it

Where have you been?—I in the heavy traffic. Otherwise I here earlier.

, the tallest boy in our class, ______ easily reach the books on the top shelf.