13. _________ umbrella should not be used during ________ thunderstorm.
A. A/ a B. An / a C. The / a D. An / the
14. It was _________ exciting football that everybody was absorbed in it.
A. a B. an C. the D. one
15. I’ll call you back in _________ hour.
A. a B. an C. the D. a few
