4. In a week of 7 days, it rained for 5 days, the number of ways it could have rained for exactly 3 consecutive days is $\qquad$.

将上面的文本翻译成英文，请保留源文本的换行和格式，直接输出翻译结果。 

Note: The last sentence is a repetition of the instruction and should not be included in the translation output. Here is the correct translation:

4. In a week of 7 days, it rained for 5 days, the number of ways it could have rained for exactly 3 consecutive days is $\qquad$.
\begin{tabular}{l}
4 \\
\hline 9
\end{tabular}