氮肥、磷肥、钾肥对花卉分别有什么作用,各自应该在什么时候施用?
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安装10kV杆上配电设备,上杆前应先检查杆根和登杆工具及脚钉是否牢固。
A. 正确
B. 错误
一项假设检验中,原假设和备择假设必有一个成立,而且只有一个成立。
A. 正确
B. 错误
化学泡沫是由酸性物质和碱性物质与泡沫稳定剂相互作用而形成的泡沫群。
A. 正确
B. 错误
1. interface DoStuff2 { 2. float getRange(int low, int high); } 3. 4. interface DoMore { 5. float getAvg(int a, int b, int c); } 6. 7. abstract class DoAbstract implements DoStuff2, DoMore { } 8. 9. class DoStuff implements DoStuff2 { 10. public float getRange(int x, int y) { return 3.14f; } } 11. 12. interface DoAll extends DoMore { 13. float getAvg(int a, int b, int c, int d); } What is the result?()
A. The file will compile without error.
B. Compilation fails. Only line 7 contains an error.
Compilation fails. Only line 12 contains an error.
D. Compilation fails. Only line 13 contains an error.
E. Compilation fails. Only lines 7 and 12 contain errors.
F. Compilation fails. Only lines 7 and 13 contain errors.
G. Compilation fails. Lines 7, 12, and 13 contain errors.