We must look into the matter at once. ✬

Do you want to look into it? ✬

Why don't you look into the problem yourself? It's your responsibility. ✬

Look into the matter more carefully. ✬

Don't look into the box. ✬

We intend to look into that matter. ✬

You should look into the matter at once. ✬

We'll look into the case at once. ✬

The detective promised to look into the matter right away. ✬

The police promised to look into the matter. ✬