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You could develop your paragraph from the starter in several ways. You might want to start by describing the reaction of the people in the room when they heard the crash. Does the baby start crying? Does someone let out a yelp or cry or some other sort of noise in reaction to the noise of the crash?
Someone probably needs to go investigating to find the source of the crash. You'll need to decide if that person can see what happened by looking out a window in the room or if the investigator needs to leave the room, unless you decide to make the crash happen within the room itself.
Are the people in the room making guesses about what happened? What are their predictions, if any? Are they talking about how loud the sound was or trying to describe what it sounded like? If the crash happened within the room, did something break to cause the crash? Was something thrown and the crash resulted? Was the crash hidden by a piece of furniture or a closet door?
You should probably conclude your paragraph by giving an explanation of what the crash was. Your investigator could come back and report to the others; someone in the room could spot the crash site while looking out the window and explain what s/he sees to the others in the room; someone could find the pieces of whatever crashed within the room.