Which one is singular?

1.'Dog $days^{\prime}$ means-

2.One of my best ¾ getting Ph.D. degree today.

3.Write the antonym of '$hazy^{\prime}.$

4.Which of the following word is an adverb?

5.The synonym of the word '$Diligent^{\prime}$ is-

6.What is the correct spelling?

7.Which one is plural?

8.Masculine gender of 'duck^{\prime} is___

9.The passive form of 'Who did $it^{\prime}$?

10.Which pair is correct? John died ___ sleep and his friend died ___ accident.

11.The meaning of "errand" is ¾

12.What ¾ last night?