ハリーポッターを核に、様々な雑誌記事など広範囲に英文に触れることで、語彙力が身に付いてゆきます。
それぞれどういう意味でしょう。
plaque
... a door on the left stood ajar, revealing a broom cupboard, and a door on the right bore a tarnished brass plaque reading: Misuse of Muggle Artefacts.[p.132, Harry Potter and the Order of the Phoenix]
One to three months after doing so, Dr Balin killed his mice and examined their brains. All the animals had developed plaques. Moreover, the longer an animal lived after the initial infection, the more plaques it had, and the larger they were.
("Alzheimer's disease", Economist Vol. 370 No. 8367, 2004)
bracket
They reached the bottom of the steps and ran along yet another corridor, which bore a great resemblance to the one that led to Snape's dungeon at Hogwarts, with rough stone walls and torches in brackets.
[from Harry Potter and the Order of the Phoenix]
The benefit to those in the higher tax bracket would persist, however, because the value of the new deduction would increase with the taxpayer's marginal tax rate. The income-tax break would be worth $5,250 for a family in the 35% tax bracket but only $1,500 for a family in the 10% bracket.
[from the New Englsih Journal of Medicine, 2007]