In the past 20 years, U. S. exports to China have increased by a factor of 12; while U. S. imports from China have increased almost 30-fold.
在过去20年里，美国对中国的出口增加了12倍，而美国从中国的进口则增加了近30倍。
2
S. brain cancer rates have dropped slightly in the past few decades even as Americans' cell phone use rose 500-fold.
过去二三十年，尽管美国的手机使用率增长了500倍之巨，但脑癌患者比例却略有下降。
3
This has likewise created a delay in the s American roll, though the Mariana plate is free to tilt and fold and is doing so, as are the plates in the northern Pacific.