A can of paint is to a paintbrush as a spool of thread is to a sewing needle. This is a relationship of function. Both show the tool needed to perform a task.
Grapes are to a pear as cheese is to butter. This relationship shows the grouping or category to which something belongs. Grapes and pears are fruit; cheese and butter are both dairy products.
An oar is to a canoe as a steering wheel is to a car. This is a functional relationship. The oar helps steer the canoe in the way that the steering wheel steers the car.
Cup is to bowl as vacuum cleaner is to broom. This is another relationship about function. The cup and bowl are both used for eating. The vacuum cleaner and broom are both used for cleaning.
A palm tree is to a pine tree as a bathing suit is to a parka. This relationship shows an opposite” warm to cold. Palm trees grow in warm climates and pine trees grow in cold climates. Bathing suits are worn in warm weather; parkas are worn in cold weather.
Batteries are to a flashlight as telephone wires are to a telephone. The batteries provide power to the flashlight; the wires send power to the telephone.
A telephone is to a stamped letter as an airplane is to a bus. A telephone and letter are both forms of communication. An airplane and bus are both forms of transportation.