Sentence:  The high voice in the night air <WSD>startled</WSD> me. Without thinking, I started to run. Then stopped. I spun around, my heart heaving against my chest. And saw a boy. About my age. 
Meaning of the word marked with <WSD> tags:  To excite by sudden alarm, surprise, or apprehension; to frighten suddenly and not seriously; to alarm; to surprise.