Supposition 假设论证
标志词 provided that…(如果) given the choice…(如果可以选择的话…)only if…(只有…)as longas…(只要) if…, suppose that…
e.g. Provided that we can minimize the pain of test animals, animalexperimentation should be continued.
e.g. Given the choice, many people would live in big cities rather than thecountryside.