(1) The magnetic field direction in coil A is upward, and when coil B is inserted, the magnetic flux in coil B becomes larger, so the magnetic field direction of induced current is downward, so the current flows through the ammeter from right to left, so the ammeter pointer deflects to the right;

(2) The coil does not move, the magnetic flux does not change and there is no induced current, so the pointer does not move;

(3) The magnetic field direction in coil A is upward, the slider moves to the left, and the current becomes larger, so the magnetic flux in coil B becomes larger, and the obstacle becomes larger, so the magnetic field direction of induced current is downward, so the current flows through the ammeter from right to left, so the pointer of the ammeter deflects to the right;

(4) The magnetic field direction in coil A is upward, and S is suddenly disconnected, so the magnetic flux is reduced and the obstruction is reduced, so the magnetic field direction of induced current is upward, so the current flows through the ammeter from left to right, so the ammeter pointer deflects to the left;

So the answers are: (1) right deviation, (2) unbiased, (3) right deviation and (4) left deviation.