cannot smile like a child, __________ a child smiles with hiseyes, while a man smiles with his lips alone.

下列各句中，没有语病的一句是（ ）

－______ you ______ my dictionary I can’t find it anywhere.－Yes. I saw it on the desk just now.

______ you are, _________ mistakes you’ll make.

made a discovery, _________ of great importance to the progress of science and technology．