1) keep your fingers crossed 两指交叉以求好运，但愿如此
Keep your fingers crossed we'll have some yummy salad to eat this summer!
希望我们夏天能有美味的沙拉吃！
2) green thumb 在种花或种菜方面很有才能
Oh wow! Well your mom has an awesome garden. I bet you have a green thumb too!
哇！你妈妈的园子很漂亮。我相信你也是种植好手！
3) lay a finger on something 碰一下
She never let me lay a finger on her garden! I've killed every house plant I've ever owned.
她根本不让我碰她的园子！我把我家的植物全都弄死了。