Therefore, the key problems in the TDDS are the development of proper auxiliary materials such as carriers, enhancers and bone materials.

这样，研制适宜的辅料如：载体、促渗材料和骨架材料等成为了研制透皮给药系统的重心。

youdao

Then it evaluates the health of infrastructure, such as the roads that mail carriers drive on.

然后，它评估基础设施的运行状况，例如邮车行驶的道路。

youdao

The wireless business is still largely about phones. But devices such as tablet computers, netbooks and e-readers are a fast-growing, if tiny, part of carriers' operations.

在手机还是无线业务最大的部分，但是类似平板电脑，上网本和电子阅读正在飞速地增长，即使小，也是运营商的一部分。

youdao

Competition has spurred innovations such as hub-and-spoke routing systems and new low-cost carriers such as Southwest Airlines and JetBlue in America and easyJet and Ryanair in Europe.

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While carriers have to pay higher subsidies for smartphones such as the iPhone, such devices allow carriers to charge customers for data plans.

WSJ: How the iPhone Zapped Carriers

The hope is that taking to the air with launch customers such as Singapore Airlines will lead to further orders from other carriers, such as Cathay Pacific and British Airways, which fly busy long-haul routes.

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