Their task is made none the easier by a widely known but unwritten rule of vegetarian cooking which permits the use of three foods from the sea--all seaweeds--but prohibits the use of three from the mountains--the important seasonings green onions, leeks, and garlic.
束手縛腳，功夫施展不易許多人都知道，烹調素食須遵守一個不成文的規矩：「海裡有三素，可用；山上有三葷，不用」。