Where the only thing she could really do in the end was get

Where the only thing she could really 【do 】in the end was get in her car, and drive off.
=Where the only thing she could really do in the end was 【to省略】get in her car, and drive off.
当不定式作表语,其前已经有实意动词do的形式时,作表语的不定式符号to经常可以省略,用作动词原形.因此,这句中使用了get,而不是to get.
What she could do then was lie down and weep.
注意：固定句式
sb can【 do nothing】 but 【do】
sb【 have/has no choice】 but 【to do 】sth
祝你开心如意!O(∩_∩)O~~