| batch |
an amount used or produced at one time. |
| expression |
the appearance of one's face at a particular moment that communicates how one feels. |
| grammar |
the rules for forming the words and sentences of a language. Some of these rules have to be learned. Other rules are already in the head of a native speaker. For example, a native English speaker would not say, "I a cat bitten by was," because the grammar does not make sense. When one learns a new language, most of the rules of its grammar have to be learned. |
| greed |
a great desire for more wealth and possessions than one needs or deserves. |
| medicine |
a drug or other substance used to treat a disease, injury, pain, or other symptoms. |
| pause |
a short stop. |
| perpetual |
lasting forever. |
| pollute |
to make dirty or harmful to health by mixing in or adding waste material. |
| pollution |
poisons, wastes, or other materials that pollute. |
| precipitation |
the act of water falling in the form of rain, snow, sleet, or hail. |
| revolutionary |
creating or leading to great change. |
| serious |
marked by careful thinking or consideration. |
| stammer |
to speak in an anxious or uncertain way. People who stammer often repeat sounds and stop between words. |
| uncover |
to discover or make known; reveal. |
| widen |
to make broader. |