| basic cause(expression, reason, importance, significance) |
| basic condition(expression, reason, importance, significance) |
| basic premise(expression, reason, importance, significance) |
| basic prerequisite(expression, reason, importance, significance) |
| basic term(expression, reason, importance, significance) |
| center piece(expression, reason, importance, significance) |
| central element(expression, reason, importance, significance) |
| chief criterion(expression, reason, importance, significance) |
| chief reason(expression, reason, importance, significance) |
| climax(noun, crisis, emergency, crunch, watershed) |
| controlling factor(expression, reason, importance, significance) |
| core driver(expression, reason, importance, significance) |
| crisis(noun, trouble, difficulty, climax, emergency) |
| critical factor(expression, reason, importance, significance) |
| critical point(noun, expression, trouble, moment, difficulty) |
| crucial component(expression, reason, importance, significance) |
| decisive factor(expression, reason, importance, significance) |
| decisive moment(noun, expression, climax, crisis, emergency) |
| determinant factor(expression, reason, importance, significance) |
| dominant cause(expression, reason, importance, significance) |