A：was the city; were the street
B：the city was; were the street
C：was the city; the streets were
D：the city was; the streets were
“森林可以涵养水源，保持水土，调节气候”这句诗体现生物多样性的（ ）
巴以冲突中的“巴”指的是____ ，“以”指的是____ ．
x－12.56＝15.7
x＝____
