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1. Mary has been staying at a homestay for three weeks during her undergraduate programme.
2. The university has been building a new campus since May.
3. He has attended two online vocational courses twice.
4. They have visited this college three times.
5. Our school has been rebuilt for our months.
Thì HTHTTD: S have/has been Ving
Thì HTHT: S have/has V3/ed
bị động thì HTHT: S have/has been V3/ed