I. Make these sentences more concise by changing negatives to positives and by clearing out clutter words and needless qualifiers. 1. I am not unappreciative of your help. 2. Do not accept a check that is not signed. 3. Our design must avoid nonconformity with building codes. 4. Never fail to wear protective clothing in the radioactive laboratory . 5. The machine will not function until the power is turned on. 6. It’s not unlikely that there will be many occurrences of this mistake . 7. It’s not unusual to find many complex sentences of this sort in professional journal s . 8. The problem of river pollution will not be solved unless the chemical factory in the upper stream is shutdown or removed .