困难的问题

• Designing a web site is a complex problem
  站点设计是一个复杂和困难的问题。
• No one can answer the difficult question
  没有人能够回答这个困难的问题。
• The teacher always picked on me to answer a hard question
  老师总是挑我回答困难的问题。
• A lot of the hardest parts of this were already done
  这其中很多最困难的问题已得到解决。
• In addition , the training of operator is also difficulty
  此外，还存在操作训练困难的问题。
• That ' s a tough one . don ' t answer yet
  这是个困难的问题，先别回答
• That is an exceedingly difficult problem
  那是个非常困难的问题。
• This is an extremely difficult problem
  这是一个极其困难的问题。
• Security is simply a hard problem
  安全性是个很困难的问题。
• Since there exists a serious problem , which is about dimension
  这里有一个很困难的问题即维数问题。