She couldn't think of the right word to substitute the other one; but what she didn't notice was that there was a thesaurus inside her desk.
I could not tell by her inscrutable smile whether she was pleased or only amused with me. The sea captain explored the inscrutable depths of the ocean searching for buried treasures.
My last apartment was very cramped, this one is more commodious.
The perceptive girl had a sense of keenness about her.
It was upon one of his walks at night that , to his surprise and delight , he serendipitously found the watch he had lost on the previous night !