单项选择题 Stainless steel is material commonly used for temperatures up to 50℃; beyond that and for severe corrosive conditions other materials are requiredThe bold and italic word “that” probably means （）.

单项选择题 Provision must be made in pipe systems for changes in length due to change of temperatureThe bold and italic word “provision” probably means （）.

单项选择题 Cast iron and gunmetal fittings are used freely in small sizes at moderate pressure; large fittings, those for high pressure and temperature are cast or mild steelIn the above sentence, the word “those” means （）.