He ________ all his authority to make them accept the plan.
A. exceeded
B. exerted
C. eases
D. enforces
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The cushion ________ open and sent feathers everywhere.
A. split
B. shifts
C. signs
D. simplifies
His ________ towards her was becoming more and more aggressive.
A. boss
B. blessing
C. band
D. behaviour
蛋白质的常见沉淀方法有______ ___、_________、_________、_________ 。(举出四种)
通常可用紫外分光光度法测定蛋白质的含量,这是因为蛋白质分子中的 、、 三种氨基酸的共轭双键有紫外吸收能力(填空用氨基酸中文名称回答)。