abstraction n. 1.抽象(作用);抽象概念;提取,抽出。 2.出神,發(fā)呆。 3.〔委婉語〕偷竊。 4.不切實(shí)際的觀念。 with an air of abstraction 茫然,呆呆地,心不在焉。 n. -ism 【美術(shù)】抽象主義;抽象派藝術(shù)。 n. -ist 抽象派畫家[藝術(shù)家]。
Two aspects of the problem are discussed : one is that lift irrigation is no need when abstraction volume capability of canal head can meet the demand ; the other is that lift irrigation is in need when abstraction volume capability of canal head can not meet the demand 它包括兩個(gè)方面:一是當(dāng)渠首可引水量能滿足灌區(qū)灌溉用水量時(shí),則不需要提水灌溉;二是當(dāng)渠首可引水量尚不能滿足灌區(qū)灌溉用水量時(shí),則需提水灌溉來補(bǔ)充灌溉用水量。