下列标准代号中,()是国家标准的代号。
A.IEEE
B.ISO
C.GB
D.GJB
参考答案:C
黄瓜定植前一周,需要降低苗床温度,适宜温度白天(),夜间()。
A.8℃,6℃
B.10℃,6℃
C.15℃,10℃
D.25℃,20℃
E-mail is a fast, cheap and convenient way to ______ messages locally and internationally.
A.give and get
B.put and get
C.send and receive
D.get in and get out