If you don't study hard from now on, your ambition to enter Tsinghua University will be just a castle in the air.

如果你不从现在开始就努力学习，你考进清华大学的抱负就是异想天开。

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The study says there must be a complete overhaul of air traffic control systems.

研究称必须对航空交通管理系统进行彻底的改革。

《柯林斯英汉双解大词典》

If you want to be an air hostess, you must have finished college study.

如果你想成为一名空姐，你必须完成大学学业。

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The Department of Agriculture, for example, provides biologists to help study wildlife that could be a danger to air travel.

VOA: special.2009.04.01

The study also noted that when tilled soil particles come in contact with air, soil organic matter is lost through the process of oxidation.

VOA: special.2010.09.28

For example, he wants to study a two thousand six agreement for an American Marine air station to move to another area of Okinawa.

VOA: special.2009.11.21

The study involved 5, 362 people between the ages of 45 and 84 living in six different cities that are part of the MESA AIR (Multi-Ethnic Study of Atherosclerosis and Air Pollution) research project, led by Joel Kaufman.

FORBES: Is Breathing Smoggy Air Hardening Your Arteries?

The Skye Air Services Feasibility Study looked at what would be needed before scheduled services could resume.

BBC: Old Man of Storr, Skye

The South African findings are broadly consistent with recent results from another investigation called the New Zealand Air Travellers Thrombosis Study.

ECONOMIST: Deep-vein thrombosis: Causing trouble | The