But all these concepts are massively expensive, require safety certification standards for road and air, need dual controls, involve complex folding wings and propellers,and have to be flown from air-strips.
2019年6月六级真题（第二套）阅读 Section A
More than drones dropping a new supply of underwear on your doorstep, Apple's massively successful brick-and-mortar-and-glass retail stores and Amazon's small steps in the same direction are what should keep old-fashioned retailers awake at night.
2019年6月六级真题（第一套）阅读 Section B
柯林斯高阶英汉双解学习词典释义
ADJ-GRADED
巨大的;庞大的;厚重的;强大的
Something that is massive is very large in size, quantity, or extent.