IV. Put the verbs in brаckets into the correct tense form: 1.I must (to say ) it's a very up-to-date design. 2. There ( to be ) color television sets with larger and smaller screens.​

1. The verb "must" indicates that the action is in the present tense and is an obligation or requirement. However, in this sentence, the auxiliary verb "to say" is in the infinitive form. To correct this, we need to change it to the correct tense form.

Solution: I must say it's a very up-to-date design.

Explanation: The verb "must" is already in the correct tense form, so we don't need to change it. We only need to change the verb "to say" to the present tense form "say" to match the tense of "must."

2. The verb "to be" is in the present simple tense, but in this sentence, it needs to be in the past simple tense.

Solution: There were color television sets with larger and smaller screens.

Explanation: The verb "to be" changes its form from "is/are" to "was/were" in the past simple tense. In this case, we use "were" because the subject "there" is plural. The sentence talks about color television sets that existed in the past, so we use the past simple tense.