Graduate tutor Lars Soderlund says non-native English speakers generally have some trouble with English grammar.

VOA: special.2009.04.30

instead of just picking up a book and trying to learn English vocabulary and English grammar structures.

而不只是拿起书，努力学习英语单词和语法结构。

如果想提高英语水平 - SpeakingMax英语口语达人

so their grammar is very ingrained in Spanish, which is different than English.

他们的语法是基于西班牙语的，与英语截然不同。

英语为什么这么难呢？ - SpeakingMax英语口语达人