15. He made ______ efforts for his degree examination and succeeded.
A. constant
B. stable
C. steady
D. regular
16. As an experienced driver, he often warns beginners not to ______ any risk.
A. receive
B. take
C. accept
D. try
17. The Chinese handicrafts he brought home are popular ______ his American friends.
A. with
B. within
C. in
D. to
18. The title of the 35th Nurse of the Year was granted to Miss Helen Taylor, who had devoted herself ______ nursing for forty years.
A. in
B. into
