根据释义及所给首字母,写出正确的单词

put something over = cover（= 盖）； at the same time as = while (= 同时)；
with a deep color = dark (= 黑)； make a hole in the ground = dig (= 挖)；
coming after; at the back = behind (= 在···后面)；
piece of metal that opens a lock = key (= 钥匙).