Earlier this year, our class ______ a

greenhouse. (visit)

Would the correct form be has visited

Yes, that's right.

wouldn't the past tense be visited?

i think 'has visited' is a past participle
not sure though :)

Oh, true. I didn't read that correctly. The form of "visit" for that particular sentence should be "visited."

The correct form would be "visited." The verb "visited" is in the past tense and is the correct form to use with the subject "our class." To form the past tense of regular verbs like "visit," you generally add "-ed" to the base form of the verb. In this case, "visit" becomes "visited." So the correct sentence would be:

"Earlier this year, our class visited a greenhouse."