学生们分组研究复杂的问题。The students work in groups on complex problems.参加者按年龄分组。Participants were categorized according to age.你的工作是把他们按字母顺序分组，然后按数字顺序排序。Your job is to group them by letter and put them in numerical order....
The miners tunnelled through the mountain to find coal.矿工在山里打通隧道找煤.The rescuers tunnelled their way ( in ) to the pot - holers.救援人员挖地道通向那些探察洞穴的人.They tunnelled along under the walls and up into the woods beyond.他们在围墙下面挖地...