问题
选择题
This outdoor training is an exercise , as we know, teenagers' confidence can be built.
A．which
B．what
C．that
D．where
答案
D
题目分析： 考查定语从句。句意：众所周知，户外锻炼是一种增强青少年自信的锻炼方式。先行词an exercise,定语从句是teenagers' confidence can be built.，不缺主干成分，故用where来引导，故选D项。
考点 : 考查定语从句