FOLLOW集的计算

<p><span style="font-family: Arial, &quot;Microsoft YaHei&quot;, SimSun, 宋体, serif; font-size: 12px; white-space: pre-wrap; background-color: rgb(255, 255, 255);">计算FOLLOW集时，为什么当有产生式</span><img src="https://edu-image.nosdn.127.net/_PhotoUploadUtils_16aa48ac-41b1-4312-924b-2bd7a8d8986e.png" style="box-sizing: initial; vertical-align: top; border: 0px; max-height: 520px; max-width: 520px; font-family: Arial, &quot;Microsoft YaHei&quot;, SimSun, 宋体, serif; font-size: 12px; white-space: pre-wrap; background-color: rgb(255, 255, 255); width: 74px; height: 23px;"/><span style="font-family: Arial, &quot;Microsoft YaHei&quot;, SimSun, 宋体, serif; font-size: 12px; white-space: pre-wrap; background-color: rgb(255, 255, 255);">&nbsp; 或者</span><img src="https://edu-image.nosdn.127.net/_PhotoUploadUtils_bc8c48ff-b3c9-4ce7-91a4-2c237790aea8.png" style="box-sizing: initial; vertical-align: top; border: 0px; max-height: 520px; max-width: 520px; font-family: Arial, &quot;Microsoft YaHei&quot;, SimSun, 宋体, serif; font-size: 12px; white-space: pre-wrap; background-color: rgb(255, 255, 255); width: 80px; height: 24px;"/><span style="font-family: Arial, &quot;Microsoft YaHei&quot;, SimSun, 宋体, serif; font-size: 12px; white-space: pre-wrap; background-color: rgb(255, 255, 255);">且</span><img src="https://edu-image.nosdn.127.net/_PhotoUploadUtils_78b13795-8ebe-471c-b690-e53367d77ae6.png" style="box-sizing: initial; vertical-align: top; border: 0px; max-height: 520px; max-width: 520px; font-family: Arial, &quot;Microsoft YaHei&quot;, SimSun, 宋体, serif; font-size: 12px; white-space: pre-wrap; background-color: rgb(255, 255, 255);"/><span style="font-family: Arial, &quot;Microsoft YaHei&quot;, SimSun, 宋体, serif; font-size: 12px; white-space: pre-wrap; background-color: rgb(255, 255, 255);">时，要将FOLLOW(A)添加至FOLLOW(B)中？</span></p>