Are these questions correct:

German grammar is simple: in that language, there are no exceptions to the rules.

Her daughter went on a diet that consisted of all fast food: hamburgers, hot dogs, and french fries.

The gardner-took the and the shovel-and began to plant the flowers.

You will need to write both-short and long-term goals.

The president-elect of the Rotary club had the winning lottery ticket.

One half of the student body attended the football game.

The ill defined terms somehow were not clear to her.

You really need to review the rules for colon and dash usage.

http://owl.english.purdue.edu/handouts/grammar/g_overvw.html

http://www.myenglishteacher.net/dashes.html

Use the links GuruBlue gave you above to help figure out the problems indicated below:

German grammar is simple: in that language, there are no exceptions to the rules. colon use is OK, but there's another error in here

Her daughter went on a diet that consisted of all fast food: hamburgers, hot dogs, and french fries. OK

The gardner-took the and the shovel-and began to plant the flowers.
not OK; read up on the difference between a dash and a hyphen and how to use each one

You will need to write both-short and long-term goals. not OK; read up on hyphen usage

The president-elect of the Rotary club had the winning lottery ticket. OK

One half of the student body attended the football game. not OK

The ill defined terms somehow were not clear to her. not OK

And here are another couple of links to help you with these punctuation marks:
http://grammar.ccc.commnet.edu/grammar/marks/dash.htm
and
" target="_blank">http://grammar.ccc.commnet.edu/grammar/marks/hyphen.htm

Let's go through each question to check if they are correct:

1. German grammar is simple: in that language, there are no exceptions to the rules.
- This sentence is using a colon correctly to introduce a clarification or explanation. However, there is another error in this sentence that needs to be addressed.

2. Her daughter went on a diet that consisted of all fast food: hamburgers, hot dogs, and french fries.
- This sentence is correct. It uses a colon to introduce a list of items.

3. The gardner-took the and the shovel-and began to plant the flowers.
- This sentence has a couple of errors. One error is the use of a hyphen instead of a dash. The other error is the placement of the dash. A dash should be placed before and after the interrupting or parenthetical phrase, not in the middle.

4. You will need to write both-short and long-term goals.
- This sentence has an error in the use of a hyphen. It should be replaced with an en dash to show a range between "short" and "long-term" goals.

5. The president-elect of the Rotary club had the winning lottery ticket.
- This sentence is correct. It uses a hyphen correctly to compound the term "president-elect."

6. One half of the student body attended the football game.
- This sentence has an error. To represent fractions, we should use a hyphen instead of "one half." So, it should be "one-half" instead.

7. The ill defined terms somehow were not clear to her.
- This sentence has a different error. It uses a hyphen instead of a dash. Additionally, "ill defined" should be hyphenated as "ill-defined."

To further understand the correct usage of colons, dashes, and hyphens, you can follow the links provided by GuruBlue above. These resources will provide explanations and examples to help you master the usage of these punctuation marks.

Let's go through the questions one by one and address the errors:

1. German grammar is simple: in that language, there are no exceptions to the rules.
The use of a colon (:) is correct here. However, there is another error in the sentence. The phrase "German grammar is simple" is incorrect because there are exceptions to the rules in German grammar.

2. Her daughter went on a diet that consisted of all fast food: hamburgers, hot dogs, and french fries.
This sentence is correct. The colon is used correctly to introduce a list.

3. The gardner-took the and the shovel-and began to plant the flowers.
The use of a hyphen (-) is incorrect here. The correct form should be "The gardener took the and the shovel and began to plant the flowers." The hyphen should be removed.

4. You will need to write both-short and long-term goals.
The use of a hyphen is incorrect here. The correct form should be "You will need to write both short- and long-term goals." The hyphen should be placed before "term" to show that it applies to both "short" and "long." Additionally, a hyphen is needed after "short" to indicate a specific type of goal.

5. The president-elect of the Rotary club had the winning lottery ticket.
This sentence is correct. There are no errors.

6. One half of the student body attended the football game.
The use of "One half" is incorrect here. The correct form should be "Half of the student body attended the football game." The word "one" is unnecessary.

7. The ill defined terms somehow were not clear to her.
The use of a hyphen is incorrect here. The correct form should be "The ill-defined terms somehow were not clear to her." A hyphen is needed to show that "ill" and "defined" are combined into a compound adjective modifying the noun "terms."

It is recommended to review the rules for colon and dash usage using the provided links.