40 POINTS!!!! Which of the following sentences is written correctly?
1:Simmer the stew {it should be steaming, but not boiling} for about 20 minutes. 2:Simmer the stew [it should be steaming, but not boiling] for about 20 minutes. 3:Simmer the stew, it should be steaming, but not boiling, for about 20 minutes. 4:Simmer the stew (it should be steaming, but not boiling) for about 20 minutes.'