although (虽然),even though(即使),
though,although在句首表“尽管”两者都可以用.
even if (=even though)
though,although,even if (though)均可引导让步状语从句,但在侧重假设或推断时要用though或as if(though),例如：
Although it rains heavily,we shall still go out
上句中although应改为even if (though)或though.
再如：Though(Even though) everyone deserts you,I will not.