A.流速逐漸加快 B.流速逐漸減慢 C.流速基本不變 D.流速先加快后減慢
A.2 B.4 C.8 D.6
A.2個(gè)與代碼相應(yīng)的信號(hào) B.3個(gè)與代碼相應(yīng)的信號(hào) C.6個(gè)與代碼相應(yīng)的信號(hào) D.8個(gè)與代碼相應(yīng)的信號(hào)