When you use "could have", do you have to use past tense to be grammatically correct? These modal verbs really confuse me because I'm not sure if I always have to match everything to the tense of the modal verb I'm using, or if I can mix and match verb tenses. Please see my examples:
I could have used the paprika in the refrigerator since it is similar to the bell pepper the recipe called for.
I could have used the paprika in the refrigerator since it was similar to bell peppers the recipe called for.
I could have used what was in the refrigerator since they are similar to what the recipe calls for.
And then with "must have," I tried to use both simple past and present continuous. Do you think the sentence below is correct?
I must have ignored my friends who were cheering on for me because I was so happy to have reached the finish line.
What about should in this sentence?
I thought I should tell you that I will be attending your party next Friday.