Checkers, known in England as draughts, is played by 2 persons who face each other across a board of 64 squares: 8 rows of 8 squares each, ___________ light and dark. Play is conducted ____ on the 32 dark squares.
Each contestant begins with 12 playing pieces, ____ called men, of one color. Whatever the opposing colors may in fact be, they are referred to as white and black. The pieces -disks _____ 2.5 cm (1 in) in diameter and ________ less than half as thick- are placed on the dark squares in the three horizontal rows nearest each player.
To win, a player must capture all the opponent's men or block them so that no further movement is possible. Black moves _____; after that, the players move ___________. A noncapturing move consists of advancing a man _________ forward to an adjacent unoccupied square. In a capturing move, a checker is jumped over an opponent's man ________ adjacent and lands on a vacant square behind that man (in the direction of the intended move).

Astronautics is that area __ engineering and technology concerned ____ spaceflight. The discipline encompasses several technical fields, including astrodynamics, propulsion, structures, power supplies, thermal control, and communications. Astrodynamics, the study __ spacecraft motion _______ force fields __ space, is the cornerstone __ astronautics.