Final answer:
In the provided sentences, the verb forms should be in the past tense. For sentence c), 'come' becomes 'came' and 'meet' becomes 'met'. For sentence d), 'start' becomes 'started' and 'try' becomes 'are trying'.
Step-by-step explanation:
The verbs in the sentences should be in the past tense as they describe events that have already happened. For sentence c), 'come' becomes 'came' and 'meet' becomes 'met'. Thus, the completed sentence would read: 'I came to John's when I met Mary last week. For sentence d), 'start' becomes 'started' and 'try' becomes 'are trying'. Therefore, the completed sentence would be: 'The game started at two o'clock. Now we are trying to do our homework.'
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