testing       
 adjective uk/ˈtes.tɪŋ/ us/ˈtes.tɪŋ/
 困难的,棘手的
difficult
  These are very testing times for our family. 这些日子是我们家极其困难的时期。 
 This testing circuit is a challenge for any racing driver. 这个测试车场对任何赛车手都是个挑战。 
 testing       
noun [ U ] uk/ˈtes.tɪŋ/ us/ˈtes.tɪŋ/
 (知识或能力)测试
the act or practice of giving tests to measure someone's knowledge or ability
  Statewide testing begins this fall. 全国考试从今年秋天开始。