Early men did not have clocks. They were told time 76. ______ by the sun and shadows of trees. At first time, they used 77. ______ sticks placed in the ground instead trees. They made 78. ______ marks in the ground, and the shadows from the sticks told 79. ______ the time of day. Later, men began to use sundials. Some of 80. ______ sundials were boxes with sticks cast a shadow. Men were 81. ______ able to take the sundial box with them. The mark for noon 82. ______ was very important. The sundials always have to face the same 83. ______ way or the time was wrong. Sundials were good only on sunny 84. ______ days, not on cloud days. They were the first kind of clock. 85. ______