Manylessonsarenowavailableonline,from

来源：语文精选馆 2.21W

Many lessons are now available online, from _____ students can choose for free.

A. whose B. which C. when D. whom

【详解】考查定语从句。句意：许多课程现在都可以在网上找到，学生们可以从中免费选择。此处是非限定*定语从句，先行词是many lessons，关系词在从句中做介词from的宾语，应使用关系代词which引导。故选B。