if;

　　unless;

　　lest;

　　provided that;

　　if it is the case;

　　in this sense;

　　once...;

　　if possible;

　　if necessary;

　　if so;

　　if not all;

　　if anything.

　　歸納總結(jié)類：

　　in other words;

　　on the whole;

　　in sum;

　　therefore;

　　hence;

　　in short;

　　in brief;

　　to sum up;

　　in conclusion;

　　in summary;

　　to conclude;

　　the conclusion can be drawn that...;

　　for this reason;

　　in short.