《煤矿安全规程》规定，维修倾斜井巷时，（）上、下段同时作业。
A.严禁
B.允许
C.不得
参考答案：A
Last Saturday, Lucy _____ in the morning, and _____ in the afternoon. [ ]
A. clean her room; go to the library
B. cleaned her room; go to the library
C. cleaned her room; went to the library
淀粉、蛋白质、脂肪这三类营养物质的化学性消化分别开始于（ ）
A．口腔、胃、小肠
B．口腔、胃、胃
C．胃、小肠、小肠
D．胃、胃、小肠
