水位降深的英文：
dropdown

The Web site uses a pair of drop-down menus to sort a list of search results by date.
这个网站使用成对的下拉菜单，根据时间对搜索结果进行排序。

The screen efficiency of the drop-down combo box allows it to do something remarkable for a control of such complexity: It can reasonably reside permanently on a program’s main screen.
组合框使用屏幕的高效率，使得这种如此复杂的控件可以做一些不平常的事情，它能合理地永久停留在程序主屏幕上。

A variant of the radio butcon is a drop-down version. Because of its similarity to the combo box control, we call this a combutcon (see Figure 21-8).
单选图标按钮的一种变体是下拉版本的，由于它和组合框控件相似，所以我们称为“组合图标按钮”（如图21-8所示）。

The application should also help him out: Data items, such as part numbers, that must be valid shouldn’t be entered through free text fields, but instead should be entered via type-ahead (auto-completion) fields or bounded controls such as drop-downs.
该应用程序还可以为这名录入员提供进一步的帮助，比如，严格要求必须有效的数字不应该在自由文本字段中键入，而是应该通过自动完成的方式、列表视图或者其他受限控件进行输入。