1. Filling the subject position, which is supposed to be a noun (phrase), with an adjective “simple”. There are two ways to fix it: (i) Use a gerund “being simple”; (ii) Use quotation marks surrounding “simple” to make it into a noun, to mean “the word ‘simple'”.

主語應為名詞而非形容詞，除非 simple 用引號表示它暫時取代了名詞，或者在它之前加上動名詞，即 “being simple”，讓它變成名詞填充主語的位置。

2. Subject-verb agreement. Phrases starting with gerund are always singular; therefore, we are changing the verb from “have” to “has”.

動詞 have 應和單數主語對應 (動名詞片語應為單數)，故應為 has。