stopAtFirst(enable = true) {
        return enable ? this.removeModifier('g') : this.addModifier('g');
    }
Default behaviour is with "g" modifier, so we can turn this another way around than other modifiers
@param {boolean} [enable=true] whether to enable this behaviour
@returns {VerbalExpression} recompiled instance of VerbalExpression
@memberof VerbalExpression