59. Gerund 

• Incorrect: I am thinking to write a novel.

 • Correct: I am thinking of writing a novel. 

• Incorrect: We were prevented from enter the room.

 • Correct: We were prevented from entering the room. A preposition is followed by a gerund (-ing forms) and not an infinitive.

 • Incorrect: They insisted on me resigning the post. 

• Correct: They insisted on my resigning the post. 

• Incorrect: They objected to John playing for the other team. 

• Correct: They objected to John's playing for the other team.  A noun or a pronoun used before a gerund should be in the possessive case. Note that the possessive case should not be used with a gerund when the gerund is in the passive or when the noun or pronoun denotes a lifeless thing. 

• Incorrect: There is no danger of the roof's crashing. 

• Correct: There is no danger of the roof crashing.