"had his algebra problems down"
达夫很快掌握了广播节目制作的技能。
His genius alone has mastered every crisis.仅凭天分，他就控制了所有的危机。
I've completely mastered the use of all the words I've learned.学过的词汇我全部掌握了.
He has mastered the ship's crew.他已能管住全体船员.
It's not difficult to understand this world when you mastered the internal relations of things.掌握了事物的内部联系你就不难理解这个世界.
She has mastered a foreign language by aid of a grammar and dictionary.她借助语法书和词典掌握了一门外语.
He has mastered enough of the complexities of arrangement to write and score a piece for a chamber music ensemble.他对改编的复杂之处已有了足够的掌握，能够谱写一部室内合奏曲了。
This fact indicates that China has already mastered, and has been continuously improving, its dispenser design technique.这些事实表明中国早已掌握并不断发展分配器设计技术.
Della, being slender, had mastered the art.德拉身材苗条, 已精通了这门子艺术.
His enthusiasm was like Spring Moon's when she had mastered a concept.他那种热情,就和春月对某事茅塞顿开的那种热情,一模一样.
He mastered several foreign languages.他掌握了几门外语.
She has fully mastered the technique.她已完全掌握了这种技术.
He had mastered various daring interjections.他学会了种种下流的感叹辞.
In the Mediterranean the U - boats were also mastered.在地中海,潜艇也被制服了.
In a single day all the outer line of the Dutch defences was mastered.在一天之内荷兰防御工事的整个外线全部被占领.
