71.______________________he called back.(about)
我正要给Tom再次打电话时,他回电话了。
72. He is _____________________that all of us like him.(so)
他是这么聪明的孩子以致于我们大家都喜欢他。
73.____________________ across the Changjiang River will be the first one for four trains to pass at the same time.(build)
正在长江大桥上面修建的那座桥将是第一座供列车通过的桥梁。