请教PP--1---81和PP--1---71

xkfy0521

81. The American clipper (ship) era was of (duration short), (extending) (from about) 1845 to 1859.

这题B该怎么改?

71.The coal industry is important to (every) industrial nations (becasue) most (other) industries are directly or indirectly (dependent) on it.

这题A该怎么改?

enjoylife517

81，词序颠倒了，应该改成short duration

71，every 跟名词单数，这里nations复数，所以改成all