Потрібно поставити речення в трьох формах the perfect tense 1.his parents enjoed travelling by sea last july 2.susan usually travels by bus or train 3 her friends travelled by bus round europe last year 4.they have just arrives

1. His parents have never enjoyed travelling by sea. - Present Perfect
By that time his parents had already enjoyed travelling by sea. Past Perfect
By Christmas his parents will have enjoyed travelling by sea. - Future Perfect
2. Susan has never travelled by train. - Present Perfect
Susan had travelled by bus. - Past P. (=Perfect)
By the end of the month Susan will have travelled by train. - Future P
3. Her friends have just travelled by bus round Europe. - Present P
By that time her friends had just travelled by bus round Europe. - Past P.
By the end of the week her friends will have travelled by bus round Europe. - Future P.
4, They have just arrived. - Present P.
By that time they had already arrived. - Past P.
They will have arrived by the end of the week. - Future P.