阅读理解,根据短文内容,填词完成句子.每空只填写一个单词.

    Xi'an is famous  all  over  the  world  for  the  terracotta  warriors  and horses.   In  1974,  when  some 

farmers were digging a well, they found some brown pottery fragments(陶器碎片),  then we discovered

the greatterracotta warriors and horses.

    Some historical books wrote that Emperor Qin Shihuang built a big tomb for himself.  He also buried a

lot of terracotta warriors and horses. However, for technical reasons, the major part of the tomb couldn't

open today.  It is still standing 76 meters high against the Mt. I.ishan and facing the Huishui River.

     After 20 years of careful excavation<挖掘)three underground vaults opened to the public in 1979,

1989, and 1994, displaying thousands of terracotta warriors, horses and chariots,  all arrang ed in battle

formations.

    Vault l, built with earth and wood, is about 210 meters long, 60 meters wide and 4.6 to 6.5 meters

high.  In this area of 12,600 square meters,  six thousand life-sized warriors and horses of terracotta were

found in different lines.  The troops were of a fairly uniform height of l.8 meters.  They helmets and armor

and carry real bows and arrows.

1. The great terracotta warriors and horses were discovered by some_     ___.

2. The major part of the tomb couldn't open today___     _ technical reasons.

3. The___      _ excavation lasted for about 20 years.

4. The No.1 Vault was__     __ with earth and wood.

5. We can see about six        of warriors and horses of terracotta in lines.