21.Every year the World Health Organization (WHO) holds an anti-tobacco in             effort to slow           effect that tobacco is having on the world’s health.

 A. an ; an   B. an; the   C. the ; an    D the ; the

22. I think that ___________ability and experience, you are abundantly competent in that job.

A. on account of    B. in spite of        C. in terms of       D. by means of

23. The number of the pets abandoned by their owners              by 30% in the recent three months because of the declining economy, according to the UK pet charity, Blue Cross.

A. is risen    B. has risen    C. rises    D. has been risen