吸气时呼吸肌的活动是 [ ]
A．肋间外肌舒张，膈肌收缩
B．肋间外肌舒张，膈肌舒张
C．肋间外肌收缩，膈肌收缩
D．肋间外肌收缩，膈肌舒张
答案：C
用括号内所给单词的适当形式填空。
1. As a driver, you should concentrate on______(drive).
2. Linda volunteered______ (help) me with my English.
3. Making friends with foreigners is a good way ______ (practice) English.
4. Shanghai is one of ______ (big) cities in the world.
5. By July last year, he______ (work) here for ten years.
真空预压施工时应同步进行地基沉降与土的侧向位移观测，施工单位按设计要求进行观测和记录，监理单位按施工单位检测数量的（）%见证检验。
A、10；
B、15；
C、20
