不确定我在这里做错了什么。无法识别扩展方法。usingSystem;usingSystem.Collections.Generic;usingSystem.Linq;usingSystem.Text;usingSystem.Text.RegularExpressions;usingStringExtensions;namespaceConsoleApplication1{classProgram{staticvoidMain(string[]args){RunTests();}staticvoidRunTests(){try{///SafeFormatSafeFormat("HiThe