Negative Prefixes and Negative Frequency Words un
+ comfortable = uncomfortable. The structure of the sentence is affirmative, but the meaning of the sentence is negative because of the negative prefix. Here are some examples of negative prefixes: Some frequently used words in English imply negation. They are words like: seldom, never, rarely, hardly, scarcely, scant Examples: Such plans have met with
scant resistance from citizens. He
hardly walks. The child
seldom laughs. My grandfather
rarely leaves the house. Avoiding Double Negatives
Occasionally you will find two negatives used correctly in an English sentence. As in math, when two negatives are together, they form a positive. The following sentences from the reading passage have two negatives, but they are correct and have a positive meaning. Example: It is not inconceivable to network multiple cameras in a single area. …businesses have been blamed for unauthorized use of electronic surveillance, and not without reason…
Even though skillful English speakers can manipulate the language, second
language learners should avoid using the double negative. Click here for Activity 4: Read this segment from an essay, and look at the ELEVEN words in yellow. Choose THE SEVEN of the yellow words with negative prefixes. When you finish, close the new window and continue to the next screen. Click here for Activity 5: Now that you've identified the seven words with negative prefix from the reading, can you match them to their definitions? When you finish, close the new window and continue to the next screen. Click here for Activity 6: Read each sentence and select the word(s) that best fill(s) in the blank(s). When you finish, close the new window and continue to the next screen. Click here for Activity 7: The following sentence contains a double negative. Form a new correct sentence using the words and phrases below. When you finish, close the new window and continue to the next screen. Click here for Activity 8: Choose the sentence that provides the best way to correct the double negative error. When you finish, close the new window and continue to the next screen.

Lecture 2
Sometimes we make a word negative by placing a negative prefix before it to change the meaning, such as:
un- un + available = unavailable il- il + logical = illogical in- in + digestible = indigestible dis- dis + loyal = disloyal non- non + living = nonliving anti- anti + slavery = antislavery
(Such plans have met with very little resistance from citizens.)
(He doesn't walk
very much.) 
(The child doesn't laugh very
often.)
(My grandfather almost never leaves the house.) 
In formal English, it is usually incorrect to use two negatives in the same sentence, so you must learn how to avoid double negatives. Sometimes English speakers substitute the word "any" for the second negative. The meaning is "zero" or "none" (not any).
Example of double negative: We don’t have no sugar in the kitchen.
Correction: We don’t have any sugar.
Meaning: It is conceivable…
Meaning: …it is with reason, or …it is reasonable…