Holiday shopping ___be a tiring experience．There are so many places to visit and choices to make．

—Look at the picture on the wall. It ________be David’s.—Yes, his name is on the first page.

 It __be the vocabulary that caused you the problem in the exercise because you know a lot of words.

If people eat natural plant poisons by mistake, they _______ go to hospital without delay.

—Why, my new computer is rubbish! Five hours has passed and it still hasn’t finished the downloading. —Don’t worry. You know, sometimes the Internet ________ be very slow.