III. Open the brackets:
1. I knew they (to wait) for me at the metro station.
2. I didn't know that you already (to wind) up the clock.
3. Sarie understood why Lanny (not to come) the previous evening.
4. She asked me if I (to remember) the legend about Merlin.
5. Father said he (can) not tell me the right time, his watch (to break).
6. I suppose they (to ring) me up after their arriving home.​

1. I knew they were waiting for me at the metro station.
Explanation: To open the brackets, we need to identify the correct form of the verb in each sentence. In this sentence, the verb "to wait" needs to be in the past tense, so we use "were waiting" to indicate that the action was happening in the past.

2. I didn't know that you had already wound up the clock.
Explanation: In this sentence, the verb "to wind" needs to be in the past perfect tense because the action of winding up the clock happened before the speaker knew about it. Therefore, we use "had wound" to indicate that the action was completed before a certain point in the past.

3. Sarie understood why Lanny had not come the previous evening.
Explanation: In this sentence, the verb "to come" needs to be in the past perfect tense because it happened before a certain point in the past. The word "not" is placed before the verb "come" to indicate that the action did not happen. Therefore, we use "had not come" to indicate that Lanny did not come before a certain point in the past.

4. She asked me if I remembered the legend about Merlin.
Explanation: In this sentence, the verb "to remember" needs to be in the past tense because it is referring to the speaker's ability to recall something in the past. Therefore, we use "remembered" to indicate that the speaker was able to recall the legend about Merlin.

5. Father said he could not tell me the right time, his watch had broken.
Explanation: In this sentence, the verb "can" needs to be in the past tense to match the context of the sentence. The word "not" is added to indicate that the action was not possible. The verb "to break" needs to be in the past perfect tense because the action of breaking the watch happened before the father said he couldn't tell the right time. Therefore, we use "had broken" to indicate that the watch was broken before a certain point in the past.

6. I suppose they will ring me up after their arrival home.
Explanation: In this sentence, the verb "to ring" needs to be in the future tense to express a possible action that is expected to happen after their arrival home. Therefore, we use "will ring" to indicate that the action of calling will happen in the future. We also use "after" to indicate that the action of calling will happen at a later point in time after their arrival home.