单词中"sten", "ften", "stle"中的字母t通常不发音：
fasten: Fasten your shoe lace before you trip over.
hasten: Jim turned up the oven heat to hasten the cooking.
glisten: Frost can glisten in the sunlight.
listen: Make sure you listen out for my call.
moisten: Moisten the cloth then clean the keyboard.
soften: Soften the butter mixture in a small saucepan.
apostle: Mark was an apostle of Christ.
thistle: Thistle plants were growing among the corn.
whistle: The referee blew his whistle at the end of the game.
wrestle: We saw the policeman wrestle the burglar to the ground.
castle: The castle lies on a hilltop.
hustle: You'll have to hustle if you're to get home for supper.
nestle: Nearby, nestling in the hills, was the children's home.
rustle: The leaves rustled in the wind.
bustle: My mother bustled around the kitchen.
gristle: Drinking chicken skin and gristle soup often can also delay the aging of skin.
mistletoe: Hanging mistletoe over a doorway during the holiday season, particularly at Christmas time, is a tradition around the world.
Christmas: Christmas is celebrated on the 25th of December.
often中的t既可发音t也可不发音：
often: They often spent Christmas together.
mortgage和chestnut中的t也不发音：
mortgage: We'll need a bigger mortgage to buy a bigger house.
chestnut: The destiny of the pest in chestnut is not known before reaching the destination.
一些单词中以t结尾的，也不发音：
Ballet, beret, depot, escargot, merlot, valet, chalet, cachet
追问没有规律么
追答1. 主要的规律就是第一条：英语单词中"sten", "ften", "stle"中的字母t通常不发音，该结构一般在词尾。但只是通常，仍有例外，还需记忆。
2. 最后一条中的词汇则是外来词汇，主要来源于法语。法语中一般以t结尾的单词都不发音，如eclat源于法语éclat [ei'kla:]。
3. 其它单词的也不多，记住mortgage、chestnut、Christmas就可以了。