After the horseplay by the wicked students, the classroom floor was strewn with crumbled chalk dust.那班顽皮学生闹著玩儿,捏碎不少粉笔,过后, 教室地板上撒满了粉笔灰.A small heart in Chalk White crystal dangles gracefully around her neck.小心脏以粉笔白色结晶优雅地垂...
The two places, he insists, are as different as chalk and cheese.他坚持说那两个地方有天壤之别。With a stick of chalk he wrote her order on a blackboard.他用一截粉笔将她的指示写在黑板上。the chalk cliffs of southern England英格兰南部的白垩质峭壁...
昆虫会使我们无法在这个世界上生存: 如果不是由于食虫动物的 保Insects would make it impossible for us to live in the world; they would devour all our crops and kill our flocks and herds , if it were not for the protection we get from insect - eating a...
Silver - coated carbonyl iron powder was prepared by using electroless plating method.用化学镀法,甲醛为还原剂,制备镀银羰基铁粉.The p - chlorophenyl isocyanate is synthesised by carbonyl chloride and p - chloroaniline . The yield is 90 %.采用...