Complete the following sentence with a (compound) word derived from the one(s) given in bracket.
Many （ ） pots in excavation（挖掘）sites are invaluable and should be well preserved.(earth)
【正确答案】：EARTHEN
【题目解析】：
根据前文的many和后文的pots（名词），空格处应该填一个形容词，earth的形容词为earthen土制的，陶制的。句意：在发掘地点挖掘出的许多陶器都是无价之宝，应该被好好保存。