應(yīng)該用my pen is missing 或者 Im missing a pen.
miss在用作丟失東西的時(shí)候通常表示一個(gè)進(jìn)行的狀態(tài),也許后面就找到了.通常是Im missing something.或者 Something is missing.
lose是指一個(gè)完成的狀態(tài),表示找過了但是沒找到.例如：I lost my pen yesterday.
try to do 和 try doing 是不同的意思：
try to do：試著做某事,也許成功也許失敗.try doing：試著用一種方法讓某事成功.
例子：
try to:I tried to open the door.
try doing:The door was stuck shut,so I tried shaking the doorknob(to see if it would open).
對于那個(gè)填空問題,可以用is 也可以用was.關(guān)鍵看時(shí)態(tài).
最后一個(gè)問題用go across the bridge或者go over the bridge.
穿過大街用 cross the street/ go across the street.