But at any moment, we are ready to act alone.

If I act alone it won't have any significant effect on the problem.

Everything was done together; no one ever had to act alone.

And in this case, the President would rather not act alone.

This does not mean that America need always act alone.

This is an area in which the Union cannot act alone, however.

And some said the Fed would not be likely to act alone.

The third will be operations in which the European forces act alone.

The police said he was acting alone while making the drug buy.

This much has been done by two people acting alone.