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 （）.

Provision must be made in pipe systems for changes in l...

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 （）.

Cast iron and gunmetal fittings are used freely in smal...

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 （）.

Wrought iron has an inherent resistance to corrosion bu...

单项选择题Wrought iron has an inherent resistance to corrosion but is not to be had freely , its place has been taken by the cuprous alloysAccording to the above sentence , which of the following statements is true?（）