Answer:
Lakeside Shopping Centre is great. I have tried on four pairs of trainers and six jackets.
Explanation:
The use of the correct form of the verb given in parenthesis is to change the given verbs in their correct tense form depending on the structure/ form of the sentence. And in the given sentence, the verbs will be used or written in their present perfect form, given that the sentence is about an action that's done in the past but has a result or effect in the present.
So, to change "try on" to the present perfect form, we must use "have/has" alongside the given verb.
Thus, the sentence will become-
Lakeside Shopping Centre is great. I have tried on four pairs of trainers and six jackets.
