He drags his leg, and he can hardly lift his arm.他拖着腿，几乎举不起他的胳膊。He took last drags at his cigarette and stood up.他抽完最后几口烟,站了起来.She always drags behind.她总是落在后头....
Barium is found in some oilfield brines in concentrations greater than 100 mg / litre.在有些油田卤水中,钡的浓度大于100毫克/升.At lower concentrations they may even be stimulants of cell division.在浓度较低时,它们甚至能促进细胞分裂.Methods Three different...