Newton was sitting under an apple tree ______ an apple fell onto his head.

A．when

B．while

C．after

D．before

下列各组词语加点字读音完全相同的一组是______。

A．积极 通缉 即使 痛心疾首

B．讴歌 欧洲 殴打 呕心沥血

C．叨扰 韬晦 饕餮 滔滔不绝

D．桑梓 渣滓 仔细 莘莘学子