用let on造句？

He let on a secret.
他泄露了一个秘密。

Let him live on.
让他生活下去。

Let him talk on.
让他说下去。

Let him talk on.
让他讲下去。

Let's get on.
我们上车吧。

Let's go on.
让我们继续下去吧！

He asked me where John was,but I didn't let on