1.permit to do 允许（做某事）
In China, no official permit to sell GM rice has ever been issued, yet GM rice has reportedly found its way into consumer markets in parts of central and southern China.
在中国，虽然还没有任何销售转基因水稻的正式许可，然而有报道说在华中和华南部分地区的市场上已经出现了转基因大米。

2.alert to 随时注意
We must be alert to the possibility of danger.
我们必须随时注意危险的可能性。

3.smile at 对...微笑
Everyone stopped to look and smile at us.
每个人都停下来看着我们，并对着我们微笑。