Modifiers matching difficulty:

• unusual,
• emotional,
• psychological,
• nutritional,
• neuropsychiatric,
• neurological,
• physical,
• personal,
• progressive,
• operational,
• educational,
• extraneous,
• real,
• serious,
• single,
• logistical,
• respiratory,
• psychiatric,
• functional,
• technical,
• economic,
• financial,
• important,
• external,
• cognitive,
• interpersonal,
• invisible,
• spiritual,
• commercial,
• experimental,
• perceptual,
• particular,
• conceptual,
• behavioural,
• sexual,
• mathematical,
• subjective,
• developmental,
• mental,
• home,
• stable,
• stressful,
• maternal,
• motor,
• unexpected,
• temporary,
• legal,
• periodic,
• past,
• ongoing,
• related,
• parental,
• secondary,
• typical,
• anatomical,
• linguistic,
• domestic,
• social,
• somatic,
• clinical,
• visual,
• prevalent,
• traditional,
• unanticipated,
• practical,
• surgical,
• basic,
• severe,
• concurrent,
• academic,
• environmental,
• acute,
• smaller,
• internal,
• special,
• underlying,
• experienced,
• regulation,
• structural,
• major,
• local,
• possible,
• persistent,
• minor,
• administrative,
• technological,
• significant,
• chronic,
• everyday,
• mechanical,
• extra,
• natural,
• habitual,
• hormonal,
• sensory,
• extreme,
• reproductive,
• common,
• computational,
• leaning,
• behavioral,
• unforeseen,

Simple categories matching past:

• event,
• movement,
• activity,
• attempt,
• perception,
• dish,
• emotion,
• war,
• experience,
• catastrophe,
• sport,
• change,
• condition,
• illness,
• measure,
• action,
• space,
• civilisation,
• organization,
• practice,
• state,
• style,
• history,
• years,
• business,
• works,
• knowledge,
• formation,
• disturbance,
• exchange,
• giant,
• obstruction,
• situation,
• disease,
• episode,
• thing,
• industry,
• relationship,
• behavior,
• difficulty,
• hazard,
• success,
• instrument,
• problem,
• happening,
• improvement,
• society,
• week,
• work,
• record,
• inhabitant,
• training,
• disaster,
• achievement,
• bill,
• competition,
• content,
• feeling,
• tradition,