是動詞時態填空吧。
應該是：
it is nacessary that he _take_some more money with him if he wants to visit more places.
意思是：
如果他想要參觀更多地方，隨身攜帶更多（足夠）的現金是必要的。
理由：
英語常見問題解答大詞典》(趙振才主編)等語法專著在介紹虛擬語氣時都提到了下面的這個用法：在It is
imperative(essential，necessary，appropnate，desirable，important，vital...等)+that引導的主語從句中謂語動詞應該用虛擬語氣的形式，即使用動詞原形或should+動詞原形。例如：
1.It is
vitally important that they receive allthe help
available.極為重要的是他們要得到所有可能得到的幫助。(《麥克米倫高階英漢雙解詞典》)
2.It is important that
you (should) keep your promise.妳應該遵守諾言，這壹點很重要。(《外研社·建宏英漢多功能詞典》)
3.The
president said it was imperative that the release of all hostag be
secured.總統說當前要務是確保所有人質都獲釋。(《劍橋高階英漢雙解詞典》)
4.It is essential that our prices
remain
competitive.我們保持價格方面的競爭優勢是至關重要的。(《劍橋高階英’漢雙解詞典》)
5.It is most desirable that they
should both come.他們兩個人都來，這最好不過了。(《牛津高階英漢雙解詞典》)
6.Il is desirable that you
should have some familiarity with
computers.妳應該對計算機知識有所熟悉，這是很有益處的。(《朗文當代高級英語辭典》)
7.It is
advisable that they go with a clearly defined goal in
mind.他們去時宜在思想上有壹個明確的目標。(《譯文·英漢大詞典》)
8.It is appropriate that the exhibition
should besponsored by BMW.這個展覽會由BMW來主辦是恰當的。(《外教社·柯林斯英漢雙解學習詞典》)