目前混凝土多采用泵送施工,为满足混凝土的可泵送要求,混凝土中常掺入()等掺合料及()或()或()等外加剂。

目前混凝土多采用泵送施工,为满足混凝土的可泵送要求,混凝土中常掺入()等掺合料及()或()或()等外加剂。

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The purpose of mentioning the Weddell Sea is___________.

The purpose of mentioning the Weddell Sea is___________.

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The phrase "prior to" (Para.2) probably means___________.

The phrase "prior to" (Para.2) probably means___________.

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