想不出

• be past recollection

例句

1. 如果你想不出什么相关事情要说，就请你安静些。
   If you can't think of anything to say that's to the purpose then please be quiet.
2. 我头脑[记忆]里（完全）是一片空白--连一个答案也想不出。
   My mind/memory was a (complete) blank I couldn't think of a single answer.