句子练习 1. The laboratory has instruments necessary for various experiments. 2. Fig.5-8 shows the loop and disk ready to start their trip down. 3. The current equals the source emf divided by the total circuit resistance, external plus internal. 4. Light, durable, simple and inexpensive, such devices are warmly received by users. 5. The conductor is moving parallel to the magnetic field. 6. The gas is restored to its original temperature, ready to repeat the cycle again and again. 7. These depressing pumps ensure contamination-free transfer of abrasive and aggressive fluids such as acids, dyes and alcohol among others. 8. Despite all the improvements, rubber still has a number of limitations. 9. High precision implies a high degree of exactness but with no implication as to accuracy.