return gift;  return favour (favor);  revenge;  change (in a cash transaction)
 now;  the present time;  just now;  another;  more
 formidable enemy;  strong enemy;  tough enemy
 special training;  intensive training;  crash course
 to tear;  to rip;  to break through (cordon, opponent's defense, etc.);  to breach;  to defeat;  to beat;  to break (e.g. silence)
 the future (usually distant);  future tense;  the world to come
 to protect;  to guard;  to defend;  to keep (i.e. a promise);  to abide (by the rules);  to observe
 time;  hour;  period;  class
 only;  merely;  but;  no more than
 downfall;  ruin;  collapse;  destruction
 artificial;  man-made;  human work;  human skill;  artificiality
 cell;  cell (in an organization, esp. a communist party)
 to steal;  to plagiarize;  to steal (a technique, idea, etc.);  to do stealthily;  to do during scant time;  to steal a base
 cooperation;  collaboration
 snare;  trap (for catching wild game, etc.);  trap (i.e. ruse, subterfuge, etc.)