请选择DCBA/c4p.F/F6O2]'P4I It’s hot _________ summer in Beijing.7y;H;D4v1}:s,s
A．by7y;H;D4v1}:s,s
B．on7y;H;D4v1}:s,s
C．at7y;H;D4v1}:s,s
D．in7y;H;D4v1}:s,s