# QUESTION
Slow-wave sleep (SWS), often referred to as deep sleep, consists of stage three (combined stages 3 and 4) of non-rapid eye movement sleep. Initially, SWS consisted of both Stage 3, which has 20-50 percent delta wave activity, and Stage 4, which has more than 50 percent delta wave activity. However, as of 2008, the American Academy of Sleep Medicine (AASM) has discontinued the use of Stage four as a separate stage. Thus, the two stages are now combined as "Stage three" or N3. An epoch (30 seconds of sleep) which consists of 20 % or more slow-wave (delta) sleep is now considered to be stage three.

Which stage of sleep is represented by delta waves?
# ANSWER
The relevant information to answer the above question is: An epoch (30 seconds of sleep) which consists of 20 % or more slow-wave (delta) sleep is now considered to be stage three.
FINAL ANSWER: three

# QUESTION
Passage: Wheatley is a fictional artificial intelligence from the Portal franchise first introduced in the 2011 video game Portal 2. He is voiced by British comedian Stephen Merchant, and created in part by Portal 2's designer Erik Wolpaw.

Question: Based on this passage, who plays the voice of wheatley in portal 2?
# ANSWER
The important part for answering this question is: He is voiced by British comedian Stephen Merchant, and created in part by Portal 2's designer Erik Wolpaw.
FINAL ANSWER: British comedian Stephen Merchant

# QUESTION
Context: The song, "I Will Always Love You" was originally written and recorded in 1973 by American singer-songwriter, Dolly Parton. Her country version of the track was released in 1974 as a single and was written as a farewell to her one-time partner and mentor of seven years, Porter Wagoner, following Parton's decision to pursue a solo career.

Question: who sang i will always love you first dolly parton or whitney houston?
# ANSWER
To answer the question, consider the following: The song, "I Will Always Love You" was originally written and recorded in 1973 by American singer-songwriter, Dolly Parton.
FINAL ANSWER: American singer - songwriter , Dolly Parton