旅游投诉是指旅游者为维护自身和他人的旅游合法权益,对损害其合法权益的旅游经营着和有关服务单位,以书面或口头形式向旅游行政管理部门提出投诉,请求处理的行为。
A. 正确
B. 错误
The CUSTOMERS table has these columns: CUSTOMER_ID NUMBER(4) NOT NULL CUSTOMER_NAME VARCHAR2(100) NOT NULL STREET_ADDRESS VARCHAR2(150) CITY_ADDRESS VARCHAR2(50) STATE_ADDRESS VARCHAR2(50) PROVINCE_ADDRESS VARCHAR2(50) COUNTRY_ADDRESS VARCHAR2(50) POSTAL_CODE VARCHAR2(12) CUSTOMER_PHONE VARCHAR2(20) The CUSTOMER_ID column is the primary key for the table. Which two statements find the number of customers? ()
A. SELECT TOTAL(*) FROM customer;
B. SELECT COUNT(*) FROM customer;
C. SELECT TOTAL(customer_id) FROM customer;
D. SELECT COUNT(customer_id) FROM customer;
E. SELECT COUNT(customers) FROM customer;
F. SELECT TOTAL(customer_name) FROM customer
吴大猷与其堂兄弟大业、大任、大立、都曾就读南开大学,被誉为“南开四吴”。
A. 正确
B. 错误
根据试验温度选用毛细管粘度计,对内径0.4mm的粘度计,试样流动时间不得少于()。
A. 350s
B. 200s
C. 400s
D. 150