It is the prevention of disease______its successful treatment that has led to the rapid increase of the world’s population.
When ______ different cultures, we often pay attention only to the differences without noticing the many similarities.
My income is rather changeable, but I earn £73 a day ___________.
Nobody knows _______broke into the house last night and stole the important papers.
—Do you think the thief entered through the back door? —No, if he had, I don’t believe he ______ the living-room window.
Go and join in the party. Leave______ to me to do the washing-up.