【简答题】As we know, it is not easy to build a satellite(卫星). Building a traditional satellite usually takes years. The costs can be as high as $250 million or more. Most members of the design teams have worke...
【简答题】Practice 3-2 Read the paragraph below carefully, try to use several appropriate transition devices in proper places to connect sentences smoothly. Daniel and I have several things in common that have ...