... Why ( was,were) some of the students excutes from the examination?6. Why ( was,were) one of the students excutes from the examination?7. What percentage of the earth’s surface (is, are) covered ... Economics (is, are) Don’s favourite subjects.16. Ten minutes (is, are) more than enough time to complete this exercise.17. Most people (likes,like) to go to the zoo.18. The police (is, are) coming. ... physical world.11. Statistics (is, are) a branch of mathematics12. Fifteen minutes (is, are) maximum length of time allowed for the exam.13. Twenty dollars (is, are) an unreasonable price for...