患者，男性，36岁。以"反复左下颌下区进食后肿痛不适半年"为主诉。患者病程中有明显的进食时左侧下颌下区肿胀疼痛，进食后数小时方可逐渐消退。临床查体见患者左下颌下腺导管开口处红肿，轻压腺体导管口溢脓，口内外双合诊于左侧口底近第一磨牙处可触及一黄豆大小硬物。

下列哪一项检查有助于确定诊断（）

A.左下颌下腺造影

B.左下颌下腺穿刺

C.下颌咬合片

D.左下颌下腺活检

E.ECT核素扫描

小题1:Mobile phones have become a problem for middle schools. In some schools the students are not allowed to carry them during school hous.

Using mobile phones gives teachers so much trouble. 小题2:The students sometimes use them to send messages or e-mails in class. Some students even use phon message cheat during exams. Therefore, 小题3:some students and their parents think they can get in touch with each other by mobile phones. They also think the students can use mobile phones to get online to study or search for inforemation.

小题4:实际上，我们能解决这个问题。  The students with mobile phones can leave phones at school offices . 小题5:或者他们可以在上课期间关机。Students can use mobile phones as long as schools let them know when they can use phones.