Like a pair of mittens, a pair of socks, a pair of earrings. Two halves of a set of chopsticks. Like the sun and the moon. Sea and the sky. Knife and fork, plates and cups, tea and coffee. Salt and pepper. Eggs and bacon. Bed and breakast. Mortar and pestle. Lock and key. Hammer and nail. Needle and thread. Bow and arrow. Sticks and stones. Cup and saucer. Shampoo and conditioner. Coffee and donuts. Tea and crumpets. Suit and tie. Straight and narrow. Spaghetti and meatballs. Song and dance. Run and hide.

An arm and a leg. An eye for an eye. Really and truly. Pots and pans. Peace and quiet. Oil and water. Noughts and crosses. A blessing and a curse. Back and forth. Back and forth. Aches and pains. Cease and desist. Search and rescue. Seek and destroy. Short and sweet. Touch and go. Young and old. Widows and orphans. True and correct. So-and-so. Safe and sound.

Alive and well.

Trial and trial and trial and trial and trial and trial and error error error error.