23. Europeans have long known that eating quail sometimes makes the eater ill, but only recently has it been established that the illness is caused by a toxin present in the quail’s body only under certain conditions.

(A) Europeans have long known that eating quail sometimes makes

(B) Europeans have long known quail eating is sometimes able to make

(C) Eating quail has long been known to Europeans to sometimes make

(D) It has long been known to Europeans that quail eating will sometimes make（A）

(E) It has long been known to Europeans that quail, when it is eaten, has sometimes made

请教NN，D错怎么什么地方呢？谢谢

D. it has long been know to Europeans 不如 Europeans have long known that 简洁

will sometimes 错误， will 表示将来， sometimes 表示一般状况。