Different festivals are ________ in different parts and countries every year.

Luckily, we’d brought a road map without _____ we would have lost our way. [ ]

The success of a government should be measured ________ the happiness of the people as well as the development of economy.[ ]

Tim is weak in math, so he is trying_________ up with other students now.

Over time the memory of the computer________so much that it never forgets anything it has been told .