radar - n. a device that uses radio signals to learn the position or speed of objects that may be too far away to be seen radiation - n. waves of ener...
rebel - v. to act against a government or power, often with force; to refuse to obey; n. one who opposes or fights against the government of his or he...
resource - n. anything of value that can be used or sold responsible - ad. having a duty or job to do ("He is responsible for preparing the repor...
sacrifice - v. to do without something or to suffer a loss for a belief, idea, goal or another person sad - ad. not happy safe - ad. away from harm or...
series - n. a number of similar things or events that follow one after another in time, position or order serious - ad. important; needing careful con...
either the right or left half of the body sign - v. to write one's name; n. a mark or shape used to mean something; evidence that something exists...
son - n. a person's male child soon - ad. not long after the present time; quickly sort - n. any group of people or things that are the same or ar...
stick - v. to attach something to another thing using a substance that will hold them together; to become fixed in one position so that movement is di...
sure - ad. very probable; with good reason to believe; true without question surface - n. the outer side or top of something ("The rocket landed ...
talk - v. to express thoughts in spoken words; n. a meeting for discussion tall - ad. higher than others; opposite short tank - n. a large container f...