Thì bị động: We don’t allow smoking in this restaurant. —> Smoking...... ; We had warned him not to go near the rivers the day before. —> He.....

1.We don’t allow smoking in this restaurant.
—> Smoking...................………..................
2.We had warned him not to go near the rivers the day before.
—> He........................................................
3.You must clean this machine every time you use it.
—> This machine........................................
4.Poets have mentioned the ao dai in poems for centuries.
—> The ao dai ............................................
5. The design and material used for men were different from those used for women.
—> The design and material used for men were not.........