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.