Wallis said:" They are one of the safest machines to fly because, if the engine stops, the rotors keep turning and you can land."
沃利斯称：“驾驶旋翼飞机很安全，即使引擎停转，旋翼还会继续转动，所以可以安全着地。”
2
Search EngineLand recently offered up 10 reasons your Web site should go mobile that are very on point, as well.
搜索引擎地带最近列出了“你的网站应该在手机上动起来的10个原因”，非常到位。
3
The team used simulation tools to show it was possible to achieve over-land flight by dramatically lowering the level of sonic booms through the use of an "inverted-V" engine-under wing configuration.