传统的电影放映是播放电影拷贝胶片上的画面，银幕上人物几秒钟的静止实际是由放映机播

单回路、串级控制系统都是（）控制

We often eat potatoes____ picnic. [ ]

A. at    

B. in    

C. in the    

D. at the

术后急性疼痛可使手术部位的肌张力增加，不利于手术后病人早期下床活动。

Which of the following statements is most accurate An intangible asset with a finite useful life is:（）

A. amortized.

B. tested for impairment at least annually.

C. amortized and tested for impairment at least annually.