<ol>
<li><p>The bus would not have had to take the long detour instead of the main highway if the bridge (did not become) treacherous in the aftermath of an ice storm</p></li>
<li><p>No one but a fool would readily lend money to a person who is known to be a frequent gambler. (No Error)</p></li>
</ol>
<p>Parenthesis is what is wrong. Can any1 explain why? For #2, shouldn't the idiom be 'known for'. I still think known to be is a wrong idiom or something..</p>
<ol>
<li>“did not become” should be in the past perfect tense: “had not become.” (This agrees with “would not have had to.”)</li>
</ol>
<p>u can refer to the thread " Post Writing Questions Here(silver turtle)"
i’ve just posted the summary of all conditional usages</p>
<p>since the event was in the past, so “did not become” should be “had not become” to indicate it was a past unreal assumption.</p>
<ol>
<li>It should be “had not become” to be parallel with “have had to take…”</li>
<li>Known “to be” is a correct idiom use in correct reference with the noun “gambler.” “Known for” could be used as in “known for his gambling skills.”</li>
</ol>
<ol>
<li>It could also be “known as.”</li>
</ol>