These two pledges are the main barrier between civil and military use of the atom.

For some, the main barrier may still be pride.

She is the main psychological barrier he has to overcome.

The report says that the old boys' network and prejudice are the main barriers to a woman's career progress.

A main barrier to the use of chemical or biological weapons has been knowledge.

The main barrier is that the asking prices are simply too high.

Your skin has a very important job: It's the main barrier protecting you from the environment.

The main barrier seems to he fear of getting non-original work - but we get that anyway.

There are two main barriers that keep the Internet from becoming profitable.

The main barrier for the installation of solar hot water systems is the initial capital investment.