每吨煤平均含30公斤氮.Every tonne of coal contains, on average, 30 kilograms of nitrogen.植物需要氮以便制造蛋白质.The plant requires nitrogen in order to make proteins.空气中所含的氮的比例是多少?What is the percentage of nitrogen in air?...
In the end, the author makes some constructive suggestions to the linkup of these two contracts.最后, 就两种合同的衔接提出了自己的一些见解.Broadcast the event on a closed circuit TV linkup.在''.'闭路电视'. ''系统上转播这次...