三相电源发出的总有功功率,等于每相电源发出的有功功率的和。()
参考答案:错
下列程序段的运行结果是:Private Sub Command1_Click() Dim n AS Integer I =21: n = 3 do while I>nI=I- n Loop Print IEnd Sub在窗体上打印的结果是______。
A.3
B.5
C.6
D.8
下面程序功能是接收数据库文件名,显示数据库的字段名、字段类型、宽度和小数位数,请阅读程序并填空: SET TALK OFF CLEAR DBNAME=SPACE(10) YN=“Y” D0 WHILE UPPER(YN);“Y” @2,16 SAY“请输入数据库文件名:”GET DBNAME READ FNAME=TRIM(DBNAME)+“.DBF.” IF.NOT.FILE(FNAME) 94,30 SAY“数据库不存在!” LOOP ENDIF USE [13] COPY T0 XYZ STRUCTURE EXTENDED USE XYZ ⑦4,10 SAY“字段名:” ①4,10 SAY“类型:” @4,10 SAY “宽度:” ⑦4,10 SAY“小数位数:” ROW=5 DO WHILE.NOT.EOF() ④ROW,10 SAY FIELD-NAME ⑦ROW,23 SAY [14] @ROW,32 SAY STR(FIELD-LEN,3) ⑦ROW,“SAY STR(FIELD-DEC,3) ROW=ROW+! SKIP ENDDO USE 9 ROW,30 SAY“是否继续(Y/N)”GET YN READ ENDDO SET TALK 0N RETURN