Final answer:
The most commonly used pliers in a shop are combination pliers, which are versatile tools that can grip and cut, and are essential for various tasks.
Step-by-step explanation:
The most commonly used pliers in a shop are the combination pliers. These pliers serve multiple purposes, which is why they are essential in many toolboxes. Combination pliers can both grip and cut, and the design allows for different tasks such as bending, compressing, or cutting wire. While slip-joint pliers are adjustable and can be used on various sizes of nuts and bolts, needle-nose pliers are used for precision work in smaller or more confined spaces, and flat-nose pliers have a flat tip for gripping flat objects. All of these types have their specific uses, but combination pliers are versatile and commonly used for a wide range of tasks.