Day 72 problematic
释义：involving problems and difficult to deal with
例句：
1-Driving in Beijing can be quite problematic.
2-Acquiring an adequate vocabulary has been highly problematic for most learners.
3-Ride-sharing services remain problematic.
4-A population-planning document released last year acknowledged that the low birth rate was problematic.
5-For firms with free products, such as Facebook and Google, such regulation could prove problematic.
练习
1-翻译：对中国学生来说，英语中的双元音（diphthong）很难掌握。
For Chinese learners, English diphthongs are rather problematic.
2-造句：改革注定困难重重。
Reforms are meant to be highly problematic.
参考翻译:
English diphthongs are particularly problematic for Chinese students to master.
