Business trips are mostly _____________. Meanwhile, the schedule is always full. A: optional B: compulsory C: empty D: friendly

中国大学MOOC: Which can fill in the blank so this code outputs Caught it?public class Tenth { public static void main(String&#91;&#93; args) { Optional opt = Optional.empty(); try { apply(opt); } catch (IllegalArgumentException e) { System.out.println(Caught it); } } private static void apply(Optional<Exception> opt) { opt._____________(IllegalArgumentException::new); }}

在XML中，在Schema中，声明一个元素的属性的attribute元素有一个常用的属性use，use的取值有（）。 A: empty B: required C: optional D: fixed E: prohibited

Which is optional on the envelop?

Optional是一种集合类型

In CNC panel, there are optional function switches.

Which of the following parts of business correspondence is optional?

grep 'line.*empty' 会匹配下列哪些行？ A: this line is empty B: this line empty C: this line.empty D: this lineempty

Which one of the following is the optional part of a business letter?

A verb phrase must contain a verb， but other elements are optional。 （ ）