The Chinese government has passed a new regulation forbidding supermarkets and stores to ______ free plastic bags to shoppers in order to protect the environment.

 Achieving a high degree of proficiency(精通）in English as a foreign language is   not a mysterious _______ without scientific basis.

 The _______ of students in our class are from the country; only five are from cities.

 —How did it _____ that you made such a silly mistake?—I myself haven’t figured it out yet.

 Nowadays, the graduate who has a good _______ of English is more likely to succeed in job hunting.