impulse
1.impulse（［情感的］冲动）后面接不定式，不接of和动名词，如可以说I cannot resist the impulse to write you again。这里的to write不可改作of writing。
2.可以说My first impulse was to say no和His first impulse was to ring me up。
3.On (an) impulse he asked me what I thought of him里的on可有可无。
