| investigate(verb, study, get, check, consider) |
| petition(noun, verb, order, go, force) |
| pump(verb, check, examine, review, challenge) |
| suspicion(noun, verb, certain, request, doubt) |
| theme(noun, point, difficulty, issue, idea) |
| canvass(verb, study, go, check, consider) |
| catechize(verb, study, check, observe, examine) |
| controvert(verb, consider, maintain, oppose, dispute) |
| cross-examine(verb, examine, review, challenge, demand) |
| demand(noun, verb, order, get, go) |
| doubtfulness(noun, certain, doubt, uncertainty, lack) |
| explore(verb, study, check, consider, maintain) |
| head(noun, point, issue, idea, material) |
| impugn(verb, get, charge, criticize, dispute) |
| interrogatory(noun, law, review, request, examination) |
| riddle(noun, difficulty, secret, puzzle, obscurity) |
| sound out(verb, expression, phrasal verb, check, see) |
| test(noun, verb, study, get, check) |
| uncertainty(noun, issue, certain, request, doubt) |
| call out(expression, verb, dispute, demand, claim) |