____________ many times, but he still couldn’t understand it.
If the printer_______ break down under guarantee, we would repair it at our expense.
— I telephoned him twice and I couldn’t get through to him.—I think that the line might have been out of order, _______?
—How do the shops make money if they sell at such low prices? —Manufacturers, it seems, are willing to bring down prices _______ big volume purchases.
It is commonly assumed that the growth of GDP and the development of people’s living conditions are not _______cause and effect.
—How much is too much for a schoolbag?—Experts say students should carry_______ more than 10 or 15 percent of their body weight.