单选题：PART FOURQuestions 21—30Read the article below about job mar

PART FOUR
Questions 21—30
•Read the article below about job market．
•Choose the correct word or phrase to fill each gap from A，B，C，or D．
•For each question 21—30，mark one letter(A，B，C，or D)on your Answer Sheet．
•There is an example at the beginning，(O)．

根据以上材料，请回答第21题：_________。