为减小渠道淤积,需要在高含沙量时,减少引水流量;在低含沙量时,加大引水流量。
参考答案:对
Questions 1-4
According to the women, what will teenagers do if they are used to a brand?()
A.Be easily affected by other products.
B.Be aware of the same kind of product.
C.Stick to that particular product.
D.Strike a bargain for other products.
男性,32岁,爆发性头痛3年;经常在夜间突然发病,无先兆,2~15min达高峰,疼痛为剧烈的、爆炸性的、不变的疼痛,偶尔呈波动性;疼痛部位通常开始于眼内、眼周围、眼部上方、或颞部,偶尔发生在面、颈、耳或头部一侧;常常伴有结膜充血和鼻塞,发病无规律,可每天发作一次或数次,可持续数周或数月,也可数月不发病。神经系统检查和辅助检查未见异常。该患者可能患有()
A.三叉神经痛
B.偏头痛
C.肌紧张性头痛
D.副鼻窦炎所致疼痛
E.丛集性头痛