1. 

2. were ( số nhiều )

3. was watching ( quá khứ tiếp diễn )

4. were 

5. was searching

6. was ( số ít )

2. 

2. Were the children hiding the treasure? ( câu hỏi thì quá khứ tiếp diễn )

3. The king and queen were not staying in the castle. ( câu phủ định )

4. we were studying at Greece. ( câu khẳng định )

5. Henry was not speaking to his brother. 

6. was she visiting the Natural History Museum?

3. 

2. they were

3. he wasn't 

4. I wasn't 

5. they were

6. they weren't

Ex 1. 

`text{2. were }`

`text{3. was watching}`

`text{4. were }`

`text{5. was searching}`

`text{6. was }`

Ex 2. 

`text{2. Were the children hiding the treasure? }`

`text{3. The king and queen were not staying in the castle. }`

`text{4. we were studying at Greece. }`

`text{5. Henry was not speaking to his brother. }`

`text{6. was she visiting the Natural History Museum?}`

Ex 3. 

`text{2. they were}`

`text{3. he wasn't }`

`text{4. I wasn't }`

`text{5. they were}`

`text{6. they weren't}`