It should be "to a/the zoo". "I once went to the zoo with my friends" describes an event that happened in the past. Additional context is needed to justify the use of the past perfect.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
Puja WahiIt means that past perfect tense can not be used without giving reference to the past tense.Roughly, yes. The thing described in the past perfect should be further back in time relative to some other past event or past point of reference. This past event or point of reference must be known from the context. Often it may be described using a past-tens