Please choose the correct ending to complete the given sentence: Computers and Electronics: [header] How to keep your laptop battery going for as long as possible [title] Unplug the battery after each use. [title] Use the hard drive more than the cd/dvd drive. [step] As power consuming as hard drives are, cd and dvd drives use more power than hard drives.

Ending1: [title] Keep a cd on if you smoke, play games, or have gaps in the battery shell. [step] For instance, if you're reading a book, the best thing to do is to delete or remove the book and create a new one. Ending2: [title] That's all that can get you going and if you very need to, just leave it behind. [title] When letting your laptop run energy saving. Ending3: Even having one in the drive can be power consuming. They spin, taking power, even when they are not actively being used. Ending4: [title] Identify any issues that will affect battery usage. [substeps] Check the temperature of your device during use to see if it is hot enough to safely run some programs.

Answer format: ending1/ending2/ending3/ending4