究竟是she is taller than he 还是she is taller than him?

究竟是she is taller than he 还是she is taller than him?
我现在初二刚刚学过，老师说"he" "he is" 和 "him"都可以的，但是学校外面的老师却说不能用"he"……都被搞糊涂了……
是现在的教材都可以写了还是我们老师说错了？谁能给我一个权威一点的答案。