--Have you seen Jack? His mother is looking for him all the afternoon.--No, I haven’t. I am sure her mother________be very worried.
What method can you think of _________ with these broken computers?
Scientists are trying their best to_______ ways to treat the terrible disease caused by Ebola(埃博拉).
—What shall we do this Saturday? — it rains, we’ll have a picnic in Century Park.
It's a pity that I didn't think of ringing you .
To remember things accurately, we don't allow other thoughts our mind.