1. The aerostat rose slowly into the air, carrying the researchers up to get a better view of the landscape.（气球缓缓升上天空，将研究人员带到更高的地方，以便更好地观察景色。）

2. The military uses aerostats for surveillance purposes, as they can stay in the air for long periods of time.（军方利用气球进行监视，因为气球可以在空中停留很长时间。）