1.The chessboard and pieces were placed so that (it, they) could be seen well.

2.The players and the observers looked at (his or her, their) watches.

3.Either the bishop or the knight will lose (its, their) powerful position.

4.Neither the players nor the observers expressed (his or her, their0 opinions.

5.A marble chess set or a wooden chess set will retain (its, their) value.

1.they
2.their
3.its
4.their
5.their

All right, except for # 5.

To determine the correct pronouns in these sentences, we need to consider the antecedents (the nouns or noun phrases that the pronouns refer to). Here's an explanation for each sentence:

1. The chessboard and pieces were placed so that (it, they) could be seen well.
Explanation: Since we are referring to both the chessboard and the pieces, which are plural, the correct pronoun to use is "they."

2. The players and the observers looked at (his or her, their) watches.
Explanation: In this case, we are referring to both the players and the observers, which are plural. Therefore, the correct pronoun to use is "their."

3. Either the bishop or the knight will lose (its, their) powerful position.
Explanation: In this sentence, we are referring to either the bishop or the knight, which is singular. Therefore, the correct pronoun to use is "its" to agree with the singular noun.

4. Neither the players nor the observers expressed (his or her, their) opinions.
Explanation: Since we are referring to both the players and the observers, which are plural, the correct pronoun to use is "their."

5. A marble chess set or a wooden chess set will retain (its, their) value.
Explanation: Here, we are referring to both a marble chess set and a wooden chess set, which means we are talking about more than one set. Therefore, the correct pronoun to use is "their" to agree with the plural noun.