Don’t touch your eyes, nose and mouth, because they aren’t covered by skin and can _______ the virus more easily.
Peter will come to understand your efforts sooner or later. It’s just a matter of _____.
Experts think that __________recently discovered painting may be ________ Picasso.
The woman stayed at home to _____ her very sick child.
The mayor is strongly opposed to _____ a new hall, which may cost a lot of money.
I can think of many cases, ________students obviously knew a lot of English words and expressions but couldn’t write a good essay.