China __________ the WTO and became a new member of it.

A．joined

B．join

C．will join

D．has joined

飞机在地面时，两边的QNH调定不一致，导致PFD上显示不同的修正气压高度，当两便高度差超过（）英尺时，ECAM上将显示BAROREFDISCREPANCY（气压基准差异）？

A、200英尺

B、300英尺

C、500英尺