“We should start back,” Gared urged as the woods began to grow dark around them.老师，urge是及物动词吗，像say,shout,call……人说话的部分前置（是宾语部分），主语+say ,shout urge..(谓语是只有及物动词）才能引出说话人说的话，是这样吗？
He must have had an accident,or he then.A.would have been hereB.had to be hereC.should be hereD.would be here请老师详细讲解这道题，为什么选A项而不能选其他项啊？这个题中then的作用是什么啊？then的用法有哪些啊？谢谢老师啦。
The rail system was chosen because the cost of energy is not so great as with a bus system because it is much easier to carry a great number of passengers by train than by bus or car, and because the noise and pollution is not so great as with buses and cars. 句中as with是什么意思？
According to Acision, the messaging and charging company of choice for over 30 network operators and service providers worldwide, the number of text messages sent during New Year’s 2008 increased 30 percent from the previous year. 请老师分析一下这个长句的结构，尤其是红体...
So I started to walk towards the garbage can I noticed a poor man walking his bike out of the restaurant in front of us.A. after B. before C. when D. whi...
...ding flow channel from central portions of the concave inner surfaces to concave corner portions facing the center of the corresponding flow channel.麻烦老师看下句子结构，实在无从下手，不知道怎么翻译。不胜感激！
Much harder,of course, is changing a system that let companies take the risks that led to the current financial crisis.老师，这个句子为什么可用Much harder做主语呢，这不是形容词吗？