Punctuation, one is taught, has a point: to   _____1_____   law and order. Punctuation marks are the road signs   _____2_____   along the highway of our communication—to control speeds, provide directions and prevent   _____3_____   collisions. A period has the unblinking finality of a red light; the comma is a flashing yellow light that asks us only to slow down; and the semicolon is a stop sign that tells us to ease gradually to a halt,   _____4_____   gradually starting up again.