1. I surf the Internet every day.
(-) I don't surf the Internet every day.
(?) Do I surf the Internet every day?

2. She is crying now.
(-) She isn't crying now.
(?) Is she crying now?

3. My sister is cleaning the floor at present.
(-) My sister isn't cleaning the floor at present.
(?) Is my sister cleaning the floor at present?

4. She saw a play yesterday.
(-) She didn't see a play yesterday.
(?) Did she see a play yesterday?

5. John caught a bird in the bushes last night.
(-) John didn't catch a bird in the bushes last night.
(?) Did John catch a bird in the bushes last night?

6. I have lived here since 1998.
(-) I haven't lived here since 1998.
(?) Have I lived here since 1998?

7. Minh has worked here for 15 years.
(-) Minh hasn't worked here for 15 years.
(?) Has Minh worked here for 15 years?