Professor Smith and Professor Brown will in giving the class lectures.A. exchangeB. alter

问题补充：

Professor Smith and Professor Brown will in giving the class lectures.

A. exchange

B. alter

C. shift

D. alternate

答案：

A. exchange

B. alter

C. shift

(答案→)D. alternate

解析：考查动词词义辨析。alternate vt./vi. 轮流，交替发生或出现；shift般动，移动（vt.）；转移到，迁移（vi.）；改变；exchange交换；exchange... for ... 用.......换......；alter(部分)修改。