Passive voice 1. Tom did a lot of homework last night 2. Bill is using the computer at the moment 3. They cancelled all flights because of fog 4. We have to test these products

1. Tom did a lot of homework last night

⇒ A lot of homework was done by Tom last night

2, Bill is using the computer at the moment

⇒ The computer is being used be Bill at the moment

3, They cancelled all flights because of fog

⇒ All flights were cancelled because of fog

4, We have to test these products

⇒ These products have to be tested

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GIẢI THÍCH:

- Dạng bị động của QKĐ:

S + was/were + V_3 + (by O)

- Dạng bị động của thì hiện tại tiếp diễn:

S + am/is/are + being + V_3 + (by O)

- Dạng bị động của động từ khiếm khuyết :

S + can/may/have to/... + be + V_3 + (by O)