Scientists will have to come_______ new methods of increasing the world’s food supply

We have been trying hard to find out the ____________of the homeless man, but without luck, no one can tell who he is.

In the past half-century, average incomes _______ quickly in developed countries, yet happiness levels have remained almost the same

ritain has agreed to join the China-led international development bank – Asian Infrastructure Investment Bank , German and Italy will follow suit.

The Great Wall winds its way from west to east, _______ deserts, _______mountains and ________valleys, until at last it reaches the sea