21. None of the sentences was/were punctuated correctly.

22. Of all her books, none have/has sold as well as the first one.

23. The number of people we need to hire is/are thirteen.

24. A number of people have/has written in about this subject.

25. Neither of them is/are available to speak right now.

26. Either of us is/are capable of doing the job.

27. There is/are four hurdles to jump.

28. There is/are a high hurdle to jump.

29. Ten dollars is/are a high price to pay.

30. Five years is/are the maximum sentence for that offense.

$\text{I. Choose the best answer by underline the word.}$

$\text{21. None of the sentences was punctuated correctly.}$

$\text{22. Of all her books, none has sold as well as the first one.}$

$\text{23. The number of people we need to hire is thirteen.}$

$\text{24. A number of people have written in about this subject.}$

$\text{25. Neither of them is available to speak right now.}$

$\text{26. Either of us is capable of doing the job.}$

$\text{27. There are four hurdles to jump.}$

$\text{28. There is a high hurdle to jump.}$

$\text{29. Ten dollars is a high price to pay.}$

$\text{30. Five years is the maximum sentence for that offense.}$