直视强烈的光线，如电焊火花、夏季中午的阳光等，都会引起眼睛损伤。
参考答案：对
—The old man is ill. He ________ to the hospital at once.
--Don’t worry. A doctor _________to come already.
A．must be sent , has asked
B．must send, have asked
C．must be sent, has been asked
D．must send, have been asked
利福霉素
A．抑制依赖DNA的RNA聚合酶B．抑制DNA回旋酶C．抑制DNA合成D．抑制二氢叶酸还原酶E．抑制二氢叶酸合成酶
