211. be on duty 值班, 值日, 在上班时

210. go on duty 上班

209. come off duty 下班

208. be due to 是由于

207. in doubt(=in a condition of uncertainty)对…表示疑惑

206. without doubt (=undoubtedly)无可置疑地

205. have…to do with 与…有关系

204. do away with(=get rid of) 除去,废除,取消; do away with (=kill) 杀掉, 镇压

203. distinguish…from 把…与…区别开

202. distinguish between (=make or recognize differences) 辨别