Identify and write the type of sentences (positive, negative, question): 1. We have been preparing for our exam since morning.

2. Have they been surfing the Net all morning?

3. Has Sam been shopping for 3 hours?

1. We have been preparing for our exam since morning.

   • Type: Positive sentence.
     This sentence affirms an ongoing action in the present perfect continuous tense, indicating that the subject ("we") has been preparing for the exam from a point in the past until now.

2. Have they been surfing the Net all morning?

   • Type: Question sentence.
     This sentence is a question in the present perfect continuous tense, asking if "they" have been engaged in the activity of surfing the internet throughout the morning.

3. Has Sam been shopping for 3 hours?

   • Type: Question sentence.
     This is another question in the present perfect continuous tense, inquiring whether "Sam" has been shopping for a duration of three hours.

The identification of sentence types is based on whether the sentence states something (positive), denies something (negative), or inquires about something (question).