1. Only few particles pass through the membrane.
2. This is the only mechanism available.
3. One may use other methods.
4. Another method was tried.
5. The other methods were not useful.
6. We used different procedures, some were useful, others failed to afford good results.
7. No evidence was presented in support of their viewpoint.
8.The article went on and on and did not say anything about anything.
9.
This is certainly no longer a system for any discussion.
