如果表达式

Returns a null string if the index is invalid or if the specified sub-expression did not participate in a match.

如果索引无效或指定的子表达式未参与到匹配中，则返回空字符串。

When in doubt, parenthesize expressions to force the grouping that the logic of your program requires.

如果有怀疑，则在表达式上按程序逻辑要求使用圆括号强制操作数的组合。

Whenever you write a macro like this, you have to remember to parenthesize all the arguments when you write the macro body; otherwise you can run into trouble when somebody calls the macro with an expression.

无论什么时候你写了象这样的宏，你必须记住在写宏体时对每个参数都要加上括号；否则，别人调用你的宏时如果用了表达式就会造成很大的麻烦。

But as soon as you want to check something deeply buried in the response DOM, regular expressions are not ideal.

但如果你想马上深入检查response DOM，正则表达式也不是很理想。

Note: At this point, the Regular Expression for matching the operators is hard-coded, and if you are adding a different set of operators, this needs to be changed in the case OPERATOR: area within ColumnOperatorValueParser.as

注意：在这一点上，匹配的经营者正则表达式是硬编码，如果您要添加一组不同的运营商，这需要在运营商改变的情况：区域内ColumnOperatorValueParser.as

A sidelight here is that if you look at the mathematical representations of a PM signal versus an FM signal, the difference is that the modulation component in a PM signal is the mathematical derivative of the modulating signal in the FM signal.

如果你看调相PM信号和调频FM信号的数字表达式的对比，它们的不同点是调相PM信号调制向量是调频FM信号调制向量的数学派生。

23 If two expressions are combined by means of the sign of equality, that means that they can be substituted for one another.

6.23 如果两个表达式用等号连接起来，这就意味着它们可以彼此代换。

If the order or the truth-possibilities in a scheme is fixed once and for all by a combinatory rule, then the last column by itself will be an expression of the truth-conditions.

如果一个图式中真值可能性的排列次序是由组合规则一次性地固定好的，那么最后一列本身就是一个真值条件的表达式。

Formerly,a sub-select or view could not be optimized very well if it appearedwithin the nullable side of an outer join and contained non-strictexpressions in its result list.

以前，如果外连接可接受空值的那一边是子查询或者视图，并且返回列表里包含不严格的表达式，总是优化的不太好。

Formerly, a sub-select or view could not be optimized very well if it appeared within the nullable side of an outer join and contained non-strict expressions in its result list.

以前，如果外连接可接受空值的那一边是子查询或者视图，并且返回列表里包含不严格的表达式，总是优化的不太好。

Do you know, i need you to come back

你知道吗，我需要你回来

Yang yinshu、Wang xiangsheng、Li decang,The first discovery of haemaphysalis conicinna.

1〕 杨银书，王祥生，李德昌。安徽省首次发现嗜群血蜱。