$$ \begin{array}{c} \text{if } A \text{ is true, then } B \text{ is true} \\ A \text{ is true} \\ \hline \text{therefore, } B \text{ is true}, \quad \colorbox{#ffff88}{(1.1)} \end{array} $$

$$ \begin{array}{c} \text{if } A \text{ is true, then } B \text{ is true} \\ B \text{ is false} \\ \hline \text{therefore, } A \text{ is false.} \quad \colorbox{#ffff88}{(1.2)} \end{array} $$