We knew that at any moment, a cousin, aunt, grandmother or stray friend might walk through out front door without knocking.

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Made of mesh, it mounts to a door so that cats can reach new heights without knocking over books or priceless antiques.

WSJ: Cat-Product Entrepreneurs Stay Steps Ahead of the Copycats

Like Vioxx, it is an arthritis drug that works by inhibiting the enzyme known as COX-2, without knocking out another enzyme called COX-1.

FORBES: Magazine Article

The justices could strike down DOMA's limits on federal recognition of same-sex marriage without upholding Proposition 8 and knocking down state-approved same-sex marriage bans.

CNN: Same-sex marriage and the Supreme Court: Key questions

He examined the screen door at the top, then, after knocking politely a few times without receiving a response, he finally redirected his eyes and discovered the man of the house vegetating placidly in his hammock, surrounded by large potted flowers and planters of ferns, in the corner of the grape arbor.

NEWYORKER: Heirs

Spurs' plan had involved knocking down most of the structure and rebuilding it without the running track, instead rebuilding the National Sports Centre at Crystal Palace.

BBC: West Ham act over stadium claims