A new __________ bus service to Tianjin Airport started to operate two months ago. 

The elderly need special care in winter, as they are        to the sudden changes of weather.

Despite being taken from very different sources, the results are remarkably _________.

Medicine should be placed where it is not ______ to children.

The witness was expected to give the police a           description of what had happened, but he was too scared to do any help.