Unlike the desertification that threatens to blanket much of north Africa continually advancing sand, even though most Middle Eastern countries features a pattern of advance and recede.
What wrong with the sentence?
To succeed in grammar questions, I thing the most important is "Vocabulary", what do you thing?
I'm sorry if the topic not clearly stated. I mean, that's all about sections in PBT Toefl test, there are three section, i.e listening, structure and written expresion, and reading. So, i have to change the topic to be
What the most important things to succeed in structure and written expresion section in the PBT Toefl test, vocabulary or the grammar?