Situations that are contrary to fact, the mood is the conditional: third type. Example: If she had got up early, she would not have missed the bus. This example illustrates an imaginary situation; it did not happen. What truly happened was that the woman got up late and missed the bus. This was the fact. The structure is : the condition introduced by "if" carries the Past Perfect and the imaginary result carries would + perfect infinitive.
Conditions under which a situation might occur, the mood is the conditional: second type. Example: If she bought an alarm clock, she would get up on time. This statement reflects a possible solution to a problem; it is a speculative solution. She does not have an alarm clock, yet if she bought one . This is the subjunctive mood . What would the result be? She would get up on time. This is the conditional mood , second type.