Check and Checkmate

Attack the general; trap it to win.

1. When a piece attacks the general, that's check (将军). The other side must answer it at once: move the general, block, or capture the attacker.
2. Checkmate means check with no way out. Find a move that checkmates Black.
3. Two chariots against a lone general. Checkmate Black in at most 4 moves — Black will defend.
4. A player has no legal move but is not in check. What happens?