It is not uncommon for there _____ problems of communication between the old and the young.
A、beingD
暂无解析
Marytiptoedoverandtooktheclockawaybecauseshehatedtohearit___whenshewastryingtogotosleep.
The opening ceremony is a great occasion. It is essential_____ for that.
The eldest child is thoroughly（）because they always give him whatever he want.
_____enoughtimeandmoney,theresearcherswouldhavebeenabletodiscovermoreinthisfield.
Ifasubstanceisdissolvedinwaterorheated，itmay（）agas.
