There be句型的主谓一致
当be后面的名词是可数名词单数或不可数名词时，谓语用单数is(was)；当be后面的名词是可数名词复数时，谓语用复数are(were)。如：
There is a river at the foot of the hill.（山脚下有条小河。）
There are two watermelons under the desk.（桌子下有两个西瓜。）
如果be后面是多个名词并列，be应与靠近它的'名词的数保持一致。如：
There is a river and many trees at the foot of the hill.（山脚下有一条小河和许多树。）
There is a basketball and two watermelons under the desk.（桌子下有一个篮球、两个西瓜。）