将下列句子变为被动语态，每空一词：
1. We can finish the work in two days.
The work ________ _________ _________ in two days.
2. They produce silk in Suzhou.
Silk _________ _________ in Suzhou.
3. The children will sing an English song. 
An English song ________ _________ ________ by the children.
4. You needn't do it now.
It _________ _________ _________ by you now.
5. Lucy sent me a New Year Card last week.
A New Year Card _________ _________ ________ me by her last week.
6. Peole use metal for making machines.
Metal _________ _________ for making machi
nes.
7. He made me do that for him.
I _________ ________ ________ _________ that for him.
8.I have given this book to the library.
This book _______ ________ ________ to the library.
9.Did they build a bridge here a year ago?
________ a bridge _________ here by them a year ago?
10.We'll put on an English play in our school.
An English play _________ __________ ___________ on in our school.
11.More and more farmers buy colour TV sets.
Colour TV sets _________ __________ __________ more and more farmers.
12.My brother often mends his watch.
His watch __________ __________ _________ by my brother.
13.We must water the flowers every day.
The flowers must ________ _________ (by us) every day.
14.They use knives for cutting things.
Knives _________ _________ for cutting things.
15.He made the farmers work for a long time.
The farmers _________ _________ __________ _________ for a long time.
16.Did he break the window yesterday?
________ the window _________ __________ __________ yesterday?
17.They have sold out the light green dresses.
The light green dresses __________ __________ __________ out.
18.We clean the classroom every day.
The classroom _________ _________ every day.
19. You must not plant trees in very dry earth.
Trees _________ _________ __________ __________ in very dry earth.
20.You can dig a hole in the earth.
A Hole _________ __________ __________ in the earth.
20
. can be dug