制冷剂充灌过多，在吸器管道表面会山现（）现象 A.结露 B.结霜 C.恒温 D.过热

很多家长热衷于把孩子送到美术班、电子琴班、舞蹈班，培养孩子各方面的潜能。下列关于潜能的说法正确的是[ ]

①人的潜能是多方面的，人的特长往往是人某个方面潜能的表现

②发现自己的潜能是取得成功的重要条件

③发掘潜能只能靠父母和学校的教育

④只有在实践中才能激发潜能，要培养有利于激发潜能的习惯，从小做起

A．①②③

B．①②④

C．②③④

D．①②③④

面部的发育始于（）

A.胚胎第2周

B.胚胎第3周

C.胚胎第4周

D.胚胎第5周

E.胚胎第6周

用酒精燃烧法测含水率试验的主要试验步骤有：①用滴管将酒精注入放有试样的称量盒中，直至盒中出现自由液面为止。为使酒精在试样中充分混合均匀，可将盒底在桌面上轻轻敲击。②取代表性试样(黏质土5～10g，砂类土20～30g)放入称量盒内，称温土质量。③将试样冷却数分钟，按第2、3步的方法重新燃烧两次。④点燃盒中酒精，燃至火焰熄灭。⑤待第三次火焰熄灭后，盖好盒盖，立即称干土质量，准确至0.1g其余同烘干法。正确的试验步骤是______。

A．②①④③⑤
B．⑤①③②④
C．③①⑤④②
D．③⑤④①②

Rapid application development (RAD) systems purport to lighten the developer’s (46) by making it easy to program an application with simple intuitive steps.
RAD tools (47) the developer everything needed to construct a fully functional application quickly and easily. They make short work of modifying the developed product to (48) changes after the program is finished. Applications developed with RAD tools are constructed as they are envisioned. As an application’s real usefulness (49) , the developer armed with RAD tools should be able to (50) on new features with little fuss.

A．burden

B．trouble

C．task

D．weight