Apair of angles can be complementary and supplementary. the answers are sometimes? always? or never true? justify the answer

 The complementary angles are those angles whose measures add up to 90 degrees, that is, if two complementary angles are in turn consecutive, the non-common sides of them form a right angle.
 Two angles are supplementary if their sum equals 180 °:
 The supplementary angles are those that added are worth two right angles, that is, 180º.
 
 A pair of angles can be never complementary and supplementary