A best friend is a very important person in our lives.

A best friend = subject
is = linking verb
a very important person = subj compl: noun
[3]

in our lives = prep phrase

Best friends are one of life’s treasures.

Best friends = subject
are = linking verb
life’s treasures = subj compl: noun
[3]

Best Friends = subject
are = linking verb
one of life’s treasures = subj compl: noun
[3]

A best friend is a real treasure.

Kennedy and Chris know the saying well.

Kennedy and Chris = subject
know = verb
the saying = object
[1]

well = adverb.

Rose is my real friend.

Rose and I like talking.

We both love dancing and listening to music.

We = subject
love = verb
dancing = gerund (object)

We = subject
[(love dancing = predicate1) and (listening to music = predicate2)]

Sometimes, Rose goes on holiday with her friends.

Sometimes = adverb at head

Rose = subject
goes = verb
[on holiday] = pre phrase
[with her friends] = prep phrase