How long does it take to have crowns fitted?

镶齿冠需要多长时间？

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How long does it take to qualify?

需要多长时间才能取得资格？

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You sneak a look at your watch to see how long you've got to wait.

你偷偷看一眼手表，看还要等多久。

《柯林斯英汉双解大词典》

They say it will help scientists better understand how to protect long-beaked echidnas and the areas where they live.

VOA: special.2009.07.07

But I don't really know about how long it would take people to hack, like, the general firewall

但我不知道人们具体要用多长时间才能穿过防火墙，

理想是当密码专家 - SpeakingMax英语口语达人

Said a different way, in the case of the straight-line programs, how long would it take to run a program?

换种说法，在直线式程序里面，运行一个程序要多长时间？

麻省理工公开课 - 计算机科学及编程导论课程节选

But, no, it took a long time to figure out how long to stir, how fast to stir.

WSJ: From Patents to Memberships, Coffee Shops Offer New Perks

With Harvey's pitch count climbing, and the temperatures dropping into the low 30s, Collins needed to figure out how long to let Harvey keep pitching.

WSJ: From Prospect to Ace in 13 Starts

Rules govern how many hamburger patties to a pound of beef (10), how long to toast a bun (17 seconds) and how much sanitizer to use when cleaning the shake machine (1 packet for 2.5 gallons of water).

FORBES: You Want Data With That?