21. When she is put in a situation ______ she has to make a remark on others, she usually changes the topic.
A. that B. when C. which D. where
22. If you don’t let out your anger or sadness, the chances are ______ you may suffer from depression over time.
A. what B. that C. whether D. when
23. ______ about the security of their children, many parents have to ask for leave to pick them up when the school is over.
A. Concerned B. To concern
C. Being concerning D. Concerning
