Using correct pronouns
Each of the children willingly did (his or her, their) share of the camp duties.
Would the correct pronoun be his or her?
Someone has left (her or his, their) automobile across the highway.
Would the correct pronoun be their?
Each of children willingly did (his or her, their) share of the camp duties.
Would the correct pronoun be their?
The first is correct. The other two are wrong. Note that the antecedent in each sentence is singular.
To determine the correct pronoun in each sentence, we need to consider the subject and the number of individuals being referred to.
For the first sentence, "Each of the children willingly did (his or her, their) share of the camp duties," we are talking about multiple children. Since we want to use a pronoun that is inclusive and doesn't assume the gender of the children, the correct pronoun would be "their." Therefore, the correct sentence would be: "Each of the children willingly did their share of the camp duties."
For the second sentence, "Someone has left (her or his, their) automobile across the highway," we are referring to a singular individual. However, we don't know the gender of the individual. In this case, it is common to use the gender-neutral pronoun "their." Therefore, the correct sentence would be: "Someone has left their automobile across the highway."
For the third sentence, "Each of children willingly did (his or her, their) share of the camp duties," it seems there is a mistake in the sentence, and "Each of" should be replaced with "Each of the." Assuming the correct sentence is "Each of the children willingly did (his or her, their) share of the camp duties," the guidance provided for the first sentence applies here as well. The correct pronoun would be "their." Therefore, the corrected sentence would be: "Each of the children willingly did their share of the camp duties."