If the variable is empty or unset, the given default value is printed instead. Default takes one argument. 当变量为空或者未分配的时候,将由给定的默认值替代输出。
Omitting the constructor argument list and enclosing parentheses is equivalent to specifying an empty argument list. For a description of a function, click a function in the list, and then click Help on this function. 删除构造函数参数列表和圆括号相当于明确一个空的参数列表。有关某一函数的说明,请单击列表中的函数,然后单击此函数上的帮助。
This is an empty argument. 这种观点很空洞。
Constrained by the morphological rules, the agent of these verbs is suppressed, leaving the position empty for the external argument. 受形态规则制约,这些动词的施事被压制,外部题元为空。