5. NaI (T1) 值測加馬射線的效率，隨加馬射線能量的增加而減少。(A)O(B)X

3. Biologists tell us that the earth has seen 500 million species of animals ____ or so. (A) during the last 3 billion years (B) it was during the last 3 billion years (C) while in the last 3 billion years (D) since the last 3 billion years