ADR所代表的是非美国公司股票的所有权。

— What have you been busy with these days?

— I ______ that the speech contest has been brought forward, so I ______ for it. [ ]

A. was informed; have been preparing  

B. have informed; am preparing

C. informed; have prepared              

D. was informed; prepared

两个同频正弦量具有相同的初相角，它们到达最大值的时间（），在相位上称这两个正弦量（）。

A typical (66) language contains an applicative sub-language which approximates the mathematical abstractions of "timeless" functions applied to "spaceless" values, where the actual operation sequences and use of storage space during expression evaluation are organized behind the (67) . In this setting, values are data structures of low volume, typically a few computer words or less, which means that an illusion of spacelessness can be realized by having (68) results during expression evalution stored at the discretion of the language implementation, and effecting parameter (69) and (70) operations through value copying.

67（）

A．foreground

B．background

C．screen

D．scenes

在word编辑中，“项目符号”的编号可以继续上面的项目编号来编号，也可以重新编号。

空气中有哪些杂质？