托盘集合包装既是包装方法，又是运输工具，又是包装容器。

某队安装480米的水管，前4天装了120米，照这样计算，安装完这水管还要多少天？

向某盐溶液中加入足量的NaOH溶液，生成红褐色沉淀，过滤后，向滤液中加入BaCl₂溶液，生成不溶于稀硝酸的白色沉淀，则该盐的化学式为（　　）

A．CuSO₄

B．AgNO₃

C．Fe₂（SO₄）₃

D．Na₂SO₄

源程序的质量要求，主要体现在源程序的()、可读性、可测试性和可维护性。

A．正确性

B．可扩展性

C．可转换性

D．兼容性

DOM is a platform-and language- (21) API that allows programs and scripts to dynamically access and update the content, structure and style of WWW documents (currently ,definitions for HTML and XML documents are part of the specification). The document can be further processed and the results of that processing can be incorporated back into the presented (22) . DOM is a (23) -based AP1 to documents, which requires the whole document to be represented in (24) while processing it. A simpler alternative to DOM is the event-based SAX, which can be used to process very large (25) documents that do not fit info the memory available for processing.

A．XML

B．HTML

C．script

D．web

明朝时杭州最大的一次西湖疏浚工程是由（）主持的，现在的西山路即由他所筑。