The children are busy doing piles of homework, for they _______ their end-of-term exam soon

Children should not have more money ___ needed.

It was along the Mississippi River ____ Mark Twain spent much of his childhood.[ ]

He began to take political science ________ only when he left school.(2013·湖北)

Newton is known as a gifted scientist with very human weaknesses who stood at the point in history _______ magic ended and science began