請教一個conditional offer的問題 - 留學

版上大大好
我是今年度申請Birmingham的新生
學校發來一封conditional offer
裡頭條件敍述如下：

Please provide an original certificate giving evidence of proficiency in the
English Language. For this programme we require 520 TOEFL with TWE 4.0 (or
IBT 68 overall with no less than 15 in any band) or 5.5 IELTS (with no less
than 5.0 in any band) or an equivalent qualification which should be no more
than two years old at the time of admission. Alternatively you can attend one
of our pre-sessional English language course. Please see page 9 of the
enclosed International and EU applicant information booklet for entry and
exit requirements for your School.

小弟不才，不懂這個conditional裡頭說IELTS 5.5以上就可以不用唸pre-sessional
還是5.5只是門檻，還要唸pre-sessional才能入學???這整句話我覺得就是一個詭異
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可以請版上有經驗的大大幫忙解釋一下嗎?
謝謝!!!

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