常用的关联词有:if(如果,假如),unless(除非,要不……就不),as long as(只要),so long as(只要),provided(that)(只要),suppose/supposing(假设),on condition(that)(如果),等。如:
I may not come to see you recently unless I can complete the project ahead of time.
除非我能提前完成那个项目,否则我最近不会来看你了。
We can surely attain our goal as long as we are united as one.
只要我们团结成一个人,我们肯定能实现我们的目标。
What shall we do if we can not get the necessary data?
如果我们弄不到必要的数据,我们怎么办?
They promised to let us have a meeting in their office on condition(that)we could keep it clean.如果我们能保持清洁,他们答应让我们在他们的办公室里开会。
注意:在表示条件的状语从句中,既有“真实条件句”,也有表示虚拟语气的“非真实条件句”。