Please choose the correct ending to complete the given sentence: Finance and Business: [header] How to use a manual can opener [title] Identify the cutting edge. [step] Generally, the cutter mechanism of the manual can opener features a sharp tip to puncture of the can lid. You may see a curved or hooked point.

Ending1: These sharp points are used for cutting cans. [substeps] For plastic cutters, the blade of the can opener is often curved. Ending2: The blade of the manual may be tilted slightly to the right or right in order to puncture the lid under normal circumstances. The sharp tip is usually capped with a laser blade. Ending3: It usually sits at the apex of the two long " arms " that you use to open and close the device. It should be situated alongside the handle, the axle, and the serrated wheel that will bite into the rim of the can lid. Ending4: Puncturing the lid will enable a trap door to open, " allowing " the food to fall to the bottom of the can, the lid opening. [title] Align the cutting edge with the lid.

Answer format: ending1/ending2/ending3/ending4