He made _____ little progress _____ his parents felt disappointed. [ ]

A. such, that

B. so, that

C. such, as

D. so, as

在共用天线系统中，不但能满足频带要求，且具有增益高、方向性好、抗干扰能力强等优点，并得到广泛应用的是（）。

A．天线阵

B．组合天线

C．X形天线

D．菱形天线