if引导条件状语从句三个时态区别

若主句为下列情形之一，条件状 语从句要用一般现在时 (1) 当主句为一般将来时：If he comes， he will bring his violin. (2) 当主句的谓语中含有 can， may， must 等情态动词时：If you lose weight， you must eat less meat. (3) 当主句为祈使句时：If you are not strong...