我在pod install时，报错信息如下：
[!] CocoaPods could not find compatible versions for pod "Alamofire":
In Podfile:
Alamofire (~> 5.2.0)
Specs satisfying the `Alamofire (~> 5.2.0)` dependency were found, but they required a higher minimum deployment target.
解决方法：
source 'https://github.com/CocoaPods/Specs.git'
platform:ios,'10.0'
use_frameworks!
target 'xiaohaoEnglish' do
pod 'Alamofire', '~> 5.2.0'
end
把platform:ios, '9.0'换成platform:ios, '10.0'就好了，主要原因是'Alamofire', '~> 5.2.0'支持的最低版本是ios 10
